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684 results on '"Centre National de la Recherche Scientifique (CNRS)"'

1. Magnetic functionalization of ZnO nanoparticles surfaces via optically generated methyl radicals

Author

D. Marin, G. Gerbaud, O. Margeat, F. Ziarelli, F. Ferrer, O. Ouari, A. Campos, S. Bertaina, A. Savoyant, Institut des Matériaux, de Microélectronique et des Nanosciences de Provence (IM2NP), Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Bioénergétique et Ingénierie des Protéines (BIP ), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Centre Interdisciplinaire de Nanoscience de Marseille (CINaM), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Centre Pluridisciplinaire de Microscopie Electronique et de Microanalyse (AMU CP2M), Aix Marseille Université (AMU), Fédération des Sciences Chimiques de Marseille (FRSCM), and Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, methyl radical, ZnO, Nanoparticles, General Physics and Astronomy, EPR, [CHIM.MATE]Chemical Sciences/Material chemistry, Physical and Theoretical Chemistry, double resonance, PACS: 31.30.Gs, 32.30.Dx, 32.80.-t 76.30.-v, 76.70.Dx
Abstract

The combination of nuclear and electron magnetic resonance techniques, in pulse and continuous wave regimes, is used to unravel the nature and features of the light-induced magnetic state arising at the surface of chemically prepared zinc oxide nanoparticles (NPs) occurring under 120 K when subjected to a sub-bandgap (405 nm) laser excitation. It is shown that the four-line structure observed around g ∼ 2.00 in the as-grown samples (beside the usual core-defect signal at g ∼ 1.96) arises from surface-located methyl radicals (•CH3), originating from the acetate capped ZnO molecules. By functionalizing the as-grown zinc oxide NPs with deuterated sodium acetate, the •CH3 electron paramagnetic resonance (EPR) signal is replaced by trideuteromethyl (•CD3). For •CH3, •CD3, and core-defect signals, an electron spin echo is detected below ∼100 K, allowing for the spin–lattice and spin–spin relaxation-time measurements for each of them. Advanced pulse-EPR techniques reveal the proton or deuteron spin-echo modulation for both radicals and give access to small unresolved superhyperfine couplings between adjacent •CH3. In addition, electron double resonance techniques show that some correlations exist between the different EPR transitions of •CH3. These correlations are discussed as possibly arising from cross-relaxation phenomena between different rotational states of radicals.

Published
2023

2. Tunability of silicon clathrate film properties by controlled guest-occupation of their cages

Author

Romain Vollondat, Daniel Stoeffler, Daniele Preziosi, Stéphane Roques, Abdelilah Slaoui, Thomas Fix, Laboratoire des sciences de l'ingénieur, de l'informatique et de l'imagerie (ICube), École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Université de Strasbourg (UNISTRA)-Institut National des Sciences Appliquées - Strasbourg (INSA Strasbourg), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Les Hôpitaux Universitaires de Strasbourg (HUS)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), and Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE)

Subjects
[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, General Physics and Astronomy, [CHIM.MATE]Chemical Sciences/Material chemistry, Physical and Theoretical Chemistry
Abstract

Type I and type II silicon clathrates are guest–host structures made of silicon polyhedral cages large enough to contain atoms that can be either inserted or evacuated with only a slight volume change of the structure. This feature is of interest not only for batteries or storage applications but also for tuning the properties of the silicon clathrate films. The thermal decomposition process can be tuned to obtain Na8Si46 and Na2

Published
2023

3. The gas-phase structure determination of α-pinene oxide: An endo-cyclic epoxide of atmospheric interest

Author

E. M. Neeman, N. Osseiran, T. R. Huet, Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523 [PhLAM], Physique Moléculaire aux Interfaces [PMI], Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523 (PhLAM), Université de Lille-Centre National de la Recherche Scientifique (CNRS), Physique Moléculaire aux Interfaces (PMI), and Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)

Subjects
[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, chemical physics, rotational spectroscopy, quantum calculations, General Physics and Astronomy, Biogenic volatile organic compounds BVOCs, Physical and Theoretical Chemistry
Abstract

International audience; The gas-phase rotational spectra of α-pinene oxide have been recorded using a chirped-pulse Fourier transform microwave spectrometer in the 6–18 GHz frequency range. The parent species and all heavy atom isotopologues (13C and 18O) have been observed in their natural abundance. The experimental rotational constants of all isotopic species observed have been determined and used to obtain the substitution (rs) and the effective (r0) structures of the most stable conformer of α-pinene oxide. Calculations using the density functional theories B3LYP, M06-2X, and MN15-L and the ab initio method MP2 level of theory were carried out to check their performance against experimental results. The structure of the heavy atom’s skeleton of α-pinene oxide has been compared to that of α-pinene and has shown that epoxidation does not overly affect the structure of the bicycle, validating its robustness. Furthermore, the structural features have been compared to those of other bicyclic molecules, such as nopinone and β-pinene.

Published
2023

4. Modeling of excited state potential energy surfaces with the Bethe-Salpeter equation formalism: The 4-(dimethylamino)benzonitrile twist

Author

Iryna Knysh, Ivan Duchemin, Xavier Blase, Denis Jacquemin, Chimie Et Interdisciplinarité : Synthèse, Analyse, Modélisation (CEISAM), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Nantes université - UFR des Sciences et des Techniques (Nantes univ - UFR ST), Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ), Laboratory of Atomistic Simulation (LSIM), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Théorie de la Matière Condensée (NEEL - TMC), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), and ANR-20-CE29-0005,BSE-forces,Géométries dans l'état excité dans le formalisme de Bethe-Salpeter(2020)

Subjects
[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, General Physics and Astronomy, Physical and Theoretical Chemistry
Abstract

We present a benchmark study of excited state potential energy surfaces (PES) using the many-body Green’s function GW and Bethe–Salpeter equation (BSE) formalisms, coupled cluster methods, as well as Time-Dependent Density Functional Theory (TD-DFT). More specifically, we investigate the evolution of the two lowest excited states of 4-(dimethylamino)benzonitrile (DMABN) upon the twisting of the amino group, a paradigmatic system for dual fluorescence and excited-state benchmarks. Our results demonstrate that the BSE/ GW approach is able to reproduce the correct topology of excited state PES upon geometry changes in both gas and condensed phases. The vertical transition energies predicted by BSE/ GW are indeed in good agreement with coupled cluster values, including triples. The BSE approach ability to include both linear response and state-specific solvent corrections further enables it to accurately describe the solvatochromism of both excited states during the twisting of DMABN. This contribution stands as one of the first proof-of-concept that BSE/ GW PES should be accurate in cases for which TD-DFT struggles, including the central case of systems embedded in a dielectric environment.

Published
2022

5. Interaction confinement and electronic screening in two-dimensional nanofluidic channels

Author

Nikita Kavokine, Paul Robin, Lydéric Bocquet, Flatiron Institute, Simons Foundation, Micromegas : Nano-Fluidique, Laboratoire de physique de l'ENS - ENS Paris (LPENS), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), and European Project: 785911,Shadoks

Subjects
Chemical Physics (physics.chem-ph), [PHYS]Physics [physics], Ions, Statistical Mechanics (cond-mat.stat-mech), Condensed Matter - Mesoscale and Nanoscale Physics, FOS: Physical sciences, General Physics and Astronomy, Water, Condensed Matter - Soft Condensed Matter, Molecular Dynamics Simulation, Electrolytes, Physics - Chemical Physics, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Soft Condensed Matter (cond-mat.soft), Physical and Theoretical Chemistry, Electronics, Condensed Matter - Statistical Mechanics
Abstract

International audience; The transport of fluids at the nanoscale is fundamental to manifold biological and industrial processes, ranging from neurotransmission to ultrafiltration. Yet, it is only recently that well-controlled channels with cross sections as small as a few molecular diameters became an experimental reality. When aqueous electrolytes are confined within such channels, the Coulomb interactions between the dissolved ions are reinforced due to dielectric contrast at the channel walls: We dub this effect “interaction confinement.” Yet, no systematic way of computing these confined interactions has been proposed beyond the limiting cases of perfectly metallic or perfectly insulating channel walls. Here, we introduce a new formalism, based on the so-called surface response functions, that expresses the effective Coulomb interactions within a two-dimensional channel in terms of the wall’s electronic structure, described to any desired level of precision. We use it to demonstrate that in few-nanometer-wide channels, the ionic interactions can be tuned by the wall material’s screening length. We illustrate this approach by implementing these interactions in Brownian dynamics simulations of a strongly confined electrolyte and show that the resulting ionic conduction can be adjusted between Ohm’s law and a Wien effect behavior. Our results provide a quantitative approach to tuning nanoscale ion transport through the electronic properties of the channel wall material.

Published
2022

6. Chemical reaction thresholds according to classical-limit quantum dynamics

Author

MAURICE MONNERVILLE, Cedric Crespos, Pascal Larregaray, Institut des Sciences Moléculaires (ISM), Université Montesquieu - Bordeaux 4-Université Sciences et Technologies - Bordeaux 1 (UB)-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523 (PhLAM), and Université de Lille-Centre National de la Recherche Scientifique (CNRS)

Subjects
[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, General Physics and Astronomy, Physical and Theoretical Chemistry
Abstract

International audience; Classical-limit quantum dynamics is used to explain the origin of the quantum thresholds of chemical reactions from their classical dynamics when these are vibrationally nonadiabatic across the interaction region. This study is performed within the framework of an elementary model of chemical reaction that mimics the passage from the free rotation of the reagents to the bending vibration at the transition state to the free rotation of the products.

Published
2022

7. Benchmarking CASPT3 vertical excitation energies

Author

Martial Boggio-Pasqua, Denis Jacquemin, Pierre-François Loos, Photochimie théorique et computationnelle (LCPQ) (PTC), Laboratoire de Chimie et Physique Quantiques Laboratoire (LCPQ), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Chimie Et Interdisciplinarité : Synthèse, Analyse, Modélisation (CEISAM), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Nantes université - UFR des Sciences et des Techniques (Nantes univ - UFR ST), Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ), Groupe Méthodes et outils de la chimie quantique (LCPQ) (GMO), and European Project: 863481,PTEROSOR

Subjects
[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Chemical Physics (physics.chem-ph), Nuclear Theory (nucl-th), Condensed Matter - Strongly Correlated Electrons, Nuclear Theory, Strongly Correlated Electrons (cond-mat.str-el), Physics - Chemical Physics, General Physics and Astronomy, FOS: Physical sciences, Physical and Theoretical Chemistry
Abstract

Based on 280 reference vertical transition energies of various natures (singlet, triplet, valence, Rydberg, $n\to\pi^*$, $\pi\to\pi^*$, and double excitations) extracted from the QUEST database, we assess the accuracy of third-order multireference perturbation theory, CASPT3, in the context of molecular excited states. When one applies the disputable ionization-potential-electron-affinity (IPEA) shift, we show that CASPT3 provides a similar accuracy as its second-order counterpart, CASPT2, with the same mean absolute error of $0.11$ eV. However, as already reported, we also observe that the accuracy of CASPT3 is almost insensitive to the IPEA shift, irrespective of the transition type and system size, with a small reduction of the mean absolute error to $0.09$ eV when the IPEA shift is switched off., Comment: 12 pages, 3 figures (supplementary material available)

Published
2022

8. The conformational landscape of myrtenol: The structure of the hydroxymethyl group and its robustness upon hydration

Author

Noureddin Osseiran, Elias Neeman, Therese Huet, Physique Moléculaire aux Interfaces (PMI), Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523 (PhLAM), and Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)

Subjects
[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Molecular Conformation, General Physics and Astronomy, Water, Hydrogen Bonding, Physical and Theoretical Chemistry, Bicyclic Monoterpenes
Abstract

The conformational landscape of myrtenol (2-pinen-10-ol) and its robustness upon hydration were investigated theoretically and experimentally by employing a synergic combination of quantum chemical calculations and Fourier transform microwave spectroscopy coupled to a supersonic jet expansion. Relaxed potential energy surfaces have been carried out, and the lowest energy conformers of the monomer were found to be associated with different geometries of the hydroxymethyl group from those previously reported [Sedo et al., J. Mol. Spectrosc. 356, 32 (2019)]. Geometry optimizations and harmonic vibrational frequency calculations allowed characterization of the equilibrium structure of the possible conformers of myrtenol. Among the nine predicted structures, four have been observed, analyzed, and identified. The controversy on the geometry was solved with the deuteration of the hydroxyl group, which led to the determination of substitution ( rs) geometry, in agreement with the present theoretical results. Interestingly, the four observed conformers exhibit the same orientation of OH as in the allyl alcohol molecule. Furthermore, hydrogen bonding linking myrtenol to water was studied. One monohydrate has been observed and identified. Non-covalent interactions and natural bond orbital analysis were performed to depict the interactions responsible for the stabilization of the observed structure. We conclude that the structure of the hydroxymethyl group is robust and does not change upon hydration.

Published
2022

9. Electron-phonon effects on the photoacoustic response of gold core-silica shell nanoparticles: From the linear regime to nanocavitation

Author

Julien Lombard, Thierry Biben, Samy Merabia, Universidad Nacional Autónoma de México (UNAM), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Universidad Nacional Autónoma de México = National Autonomous University of Mexico (UNAM), Modélisation de la matière condensée et des interfaces (MMCI), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and European Project: 766853,H2020-FETOPEN-1-2016-2017,EFINED(2018)

Subjects
[PHYS]Physics [physics], Nanofluidics, General Physics and Astronomy, Acoustics, Thermodynamic properties, Thermal conductivity, Photoacoustic effects, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], Heat transfer, Finite difference methods, Cavitation bubbles, Phonons, Nanoparticles, Physical and Theoretical Chemistry, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat]
Abstract

International audience; Coating gold nanostructures with a silica shell has been long considered for biomedical applications, including photoacoustic imaging. Recent experimental and modeling investigations reported contradicting results concerning the effect of coating on the photoacoustic response of gold nanostructures. Enhanced photoacoustic response is generally attributed to facilitated heat transfer at the gold/silica/water system. Here, we examine the photoacoustic response of gold core–silica shell nanoparticles immersed in water using a combination of the two temperature model and hydrodynamic phase field simulations. Here, of particular interest is the role of the interfacial coupling between the gold electrons and silica shell phonons. We demonstrate that as compared to uncoated nanoparticles, photoacoustic response is enhanced for very thin silica shells (5 nm) and short laser pulses, but for thicker coatings, the photoacoustic performance are generally deteriorated. We extend the study to the regime of nanocavitation and show that the generation of nanobubbles may also play a role in the enhanced acoustic response of core–shell nanoparticles. Our modeling effort may serve as guides for the optimization of the photoacoustic response of heterogeneous metal–dielectric nanoparticles.

Published
2022

10. Impact of the local atomic structure on the thermal conductivity of amorphous Ge2Sb2Te5

Author

Mohammed Guerboub, Steve Dave Wansi Wendji, Carlo Massobrio, Assil Bouzid, Mauro Boero, Guido Ori, Evelyne Martin, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des sciences de l'ingénieur, de l'informatique et de l'imagerie (ICube), École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Université de Strasbourg (UNISTRA)-Institut National des Sciences Appliquées - Strasbourg (INSA Strasbourg), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Les Hôpitaux Universitaires de Strasbourg (HUS)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE)

Subjects
[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, General Physics and Astronomy, Physical and Theoretical Chemistry
Abstract

Thermal properties are expected to be sensitive to the network topology, and however, no clearcut information is available on how the thermal conductivity of amorphous systems is affected by details of the atomic structure. To address this issue, we use as a target system a phase-change amorphous material (i.e., Ge2Sb2Te5) simulated by first-principles molecular dynamics combined with the approach-to-equilibrium molecular dynamics technique to access the thermal conductivity. Within the density-functional theory, we employed two models sharing the same exchange-correlation functional but differing in the pseudopotential (PP) implementation [namely, Trouiller–Martins (TM) and Goedecker, Teter, and Hutter (GTH)]. They are both compatible with experimental data, and however, the TM PP construction results in a Ge tetrahedral environment largely predominant over the octahedral one, although the proportion of tetrahedra is considerably smaller when the GTH PP is used. We show that the difference in the local structure between TM and GTH models impacts the vibrational density of states while the thermal conductivity does not feature any appreciable sensitivity to such details. This behavior is rationalized in terms of extended vibrational modes.

Published
2023

11. A molecular perspective on induced charges on a metallic surface

Author

Giovanni Pireddu, Laura Scalfi, Benjamin Rotenberg, PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Freie Universität Berlin, Réseau sur le stockage électrochimique de l'énergie (RS2E), Université de Nantes (UN)-Aix Marseille Université (AMU)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Université de Picardie Jules Verne (UPJV)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA), Université de Picardie Jules Verne (UPJV)-Institut de Chimie du CNRS (INC)-Aix Marseille Université (AMU)-Université de Pau et des Pays de l'Adour (UPPA)-Université de Nantes (UN)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Institut National Polytechnique (Toulouse) (Toulouse INP), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)

Subjects
Materials science, Chemical physics, General Physics and Astronomy, FOS: Physical sciences, Solvation, 02 engineering and technology, Molecular dynamics, 010402 general chemistry, 01 natural sciences, Metallic solids, Ion, Electrolytes, Electrostatics, Physics::Plasma Physics, Physics - Chemical Physics, Electric field, Physical and Theoretical Chemistry, Physics::Chemical Physics, Chemical Physics (physics.chem-ph), 500 Naturwissenschaften und Mathematik::530 Physik::539 Moderne Physik, Screening effect, Charge density, Bonding in solids, Electrostatic induction, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Solvent models, Dielectric properties, Molecular simulations, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], 0210 nano-technology
Abstract

International audience; Understanding the response of the surface of metallic solids to external electric field sources is crucial to characterize electrode–electrolyte interfaces. Continuum electrostatics offer a simple description of the induced charge density at the electrode surface. However, such a simple description does not take into account features related to the atomic structure of the solid and to the molecular nature of the solvent and of the dissolved ions. In order to illustrate such effects and assess the ability of continuum electrostatics to describe the induced charge distribution, we investigate the behavior of a gold electrode interacting with sodium or chloride ions fixed at various positions, in a vacuum or in water, using all-atom constant-potential classical molecular dynamics simulations. Our analysis highlights important similarities between the two approaches, especially under vacuum conditions and when the ion is sufficiently far from the surface, as well as some limitations of the continuum description, namely, neglecting the charges induced by the adsorbed solvent molecules and the screening effect of the solvent when the ion is close to the surface. While the detailed features of the charge distribution are system-specific, we expect some of our generic conclusions on the induced charge density to hold for other ions, solvents, and electrode surfaces. Beyond this particular case, the present study also illustrates the relevance of such molecular simulations to serve as a reference for the design of improved implicit solvent models of electrode–electrolyte interfaces.

Published
2021

12. Accurate full configuration interaction correlation energy estimates for five- and six-membered rings

Author

Yann Damour, Anthony Scemama, Mickaël Véril, Denis Jacquemin, Michel Caffarel, F. Kossoski, Pierre-François Loos, Groupe Méthodes et outils de la chimie quantique (LCPQ) (GMO), Laboratoire de Chimie et Physique Quantiques Laboratoire (LCPQ), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), European Project: 863481,PTEROSOR, European Project: 95216,TREX, Laboratoire de Chimie et Physique Quantiques (LCPQ), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)

Subjects
Work (thermodynamics), Nuclear Theory, FOS: Physical sciences, General Physics and Astronomy, 010402 general chemistry, 01 natural sciences, Full configuration interaction, Quantum chemistry, Molecular physics, Nuclear Theory (nucl-th), Pyridazine, Condensed Matter - Strongly Correlated Electrons, chemistry.chemical_compound, Physics - Chemical Physics, 0103 physical sciences, Limit (mathematics), Physical and Theoretical Chemistry, Basis set, Chemical Physics (physics.chem-ph), Physics, Quantum Physics, Strongly Correlated Electrons (cond-mat.str-el), 010304 chemical physics, Series (mathematics), Computational Physics (physics.comp-ph), Configuration interaction, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, chemistry, Quantum Physics (quant-ph), Physics - Computational Physics
Abstract

Following our recent work on the benzene molecule [\href{https://doi.org/10.1063/5.0027617}{J.~Chem.~Phys.~\textbf{153}, 176101 (2020)}], itself motivated by the blind challenge of Eriksen \textit{et al.} [\href{https://doi.org/10.1021/acs.jpclett.0c02621}{J.~Phys.~Chem.~Lett.~\textbf{11}, 8922 (2020)}] on the same system, we report accurate full configuration interaction (FCI) frozen-core correlation energy estimates for twelve five- and six-membered ring molecules in the standard correlation-consistent double-$\zeta$ Dunning basis set (cc-pVDZ). Our FCI correlation energy estimates, with estimated error smaller than 1 millihartree, are based on energetically optimized-orbital selected configuration interaction (SCI) calculations performed with the \textit{Configuration Interaction using a Perturbative Selection made Iteratively} (CIPSI) algorithm. Having at our disposal these accurate reference energies, the respective performance and convergence properties of several popular and widely-used families of single-reference quantum chemistry methods are investigated. In particular, we study the convergence properties of i) the M{\o}ller-Plesset perturbation series up to fifth-order (MP2, MP3, MP4, and MP5), ii) the iterative approximate coupled-cluster series CC2, CC3, and CC4, and iii) the coupled-cluster series CCSD, CCSDT, and CCSDTQ. The performance of the ground-state gold standard CCSD(T) as well as the completely renormalized CC model, CR-CC(2,3), are also investigated., Comment: 13 pages, 5 figures

Published
2021

13. The localization spread and polarizability of rings and periodic chains

Author

Celestino Angeli, Gian Luigi Bendazzoli, Stefano Evangelisti, J. Arjan Berger, Dipartimento di Scienze Chimiche e Farmaceutiche, Università degli Studi di Ferrara = University of Ferrara (UniFE), Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), Groupe Méthodes et outils de la chimie quantique (LCPQ) (GMO), Laboratoire de Chimie et Physique Quantiques Laboratoire (LCPQ), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), and European Theoretical Spectroscopy Facility (ETSF)

Subjects
Physics, Finite ring, localization spread, Mathematical analysis, Position operator, General Physics and Astronomy, Second moment of area, FOS: Physical sciences, metallic and insulating behavior, periodic chains, polarizability, NO, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Condensed Matter - Other Condensed Matter, Polarizability, Position (vector), Periodic boundary conditions, PE2_7, Boundary value problem, Physical and Theoretical Chemistry, Quantum, ComputingMilieux_MISCELLANEOUS, localization spread, polarizability, periodic chains, metallic and insulating behavior, Other Condensed Matter (cond-mat.other), PE5_2
Abstract

The localization spread gives a criterion to decide between metallic and insulating behavior of a material. It is defined as the second moment cumulant of the many-body position operator, divided by the number of electrons. Different operators are used for systems treated with open or periodic boundary conditions. In particular, in the case of periodic systems, we use the complex position definition, which was already used in similar contexts for the treatment of both classical and quantum situations. In this study, we show that the localization spread evaluated on a finite ring system of radius R with open boundary conditions leads, in the large R limit, to the same formula derived by Resta and co-workers [C. Sgiarovello, M. Peressi, and R. Resta, Phys. Rev. B 64, 115202 (2001)] for 1D systems with periodic Born–von Karman boundary conditions. A second formula, alternative to Resta’s, is also given based on the sum-over-state formalism, allowing for an interesting generalization to polarizability and other similar quantities.

Published
2021

14. Impact of the electric field on isotropic and anisotropic spin Hamiltonian parameters

Author

Barthélémy Pradines, Benjamin Cahier, Nicolas Suaud, Nathalie Guihéry, Systèmes étendus et magnétisme (LCPQ) (SEM), Laboratoire de Chimie et Physique Quantiques Laboratoire (LCPQ), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), and ANR-20-CE29-0010,SMolMagIQ,Molécules magnétiques commutables pour l'information quantique(2020)

Subjects
[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, General Physics and Astronomy, Physical and Theoretical Chemistry
Abstract

One may obviously think that the best way to control magnetic properties relies on using a magnetic field. However, it is not convenient to focus a magnetic field on a small object, whereas it is much easier to do so with an electric field. Magnetoelectric coupling allows one to control the magnetization with the electric field and the polarization with the magnetic field and could therefore provide a solution to this problem. This paper aims at quantifying the impact of the electric field on both the isotropic magnetic exchange and the Dzyaloshinskii–Moriya interaction in the case of a binuclear system of S = 1/2 spins. This study follows previous studies that showed that very high Dzyaloshinskii–Moriya interaction, i.e., the antisymmetric exchange, can be generated when close to first order spin orbit coupling. We will, therefore, explore this regime in a model Cu(II) complex that exhibits a quasi-degeneracy of the [Formula: see text] and d xy orbitals. This situation is indeed the one that allows us to obtain the largest spin orbit couplings in transition metal complexes. We will show that both the magnetic exchange and the Dzyaloshinskii–Moriya interaction are very sensitive to the electric field and that it would therefore be possible to modulate and control magnetic properties by the electric field. Finally, rationalizations of the obtained results will be proposed.

Published
2022

15. The Wigner localization of interacting electrons in a one-dimensional harmonic potential

Author

Xabier Telleria-Allika, Miguel Escobar Azor, Grégoire François, Gian Luigi Bendazzoli, Jon M. Matxain, Xabier Lopez, Stefano Evangelisti, J. Arjan Berger, Donostia International Physics Center (DIPC), University of the Basque Country/Euskal Herriko Unibertsitatea (UPV/EHU), Groupe Méthodes et outils de la chimie quantique (LCPQ) (GMO), Laboratoire de Chimie et Physique Quantiques Laboratoire (LCPQ), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), University of Bologna/Università di Bologna, and ANR-19-CE30-0011,TRIXS,Description théorique de la diffusion inélastique des rayons X(2019)

Subjects
Condensed Matter - Strongly Correlated Electrons, Strongly Correlated Electrons (cond-mat.str-el), FOS: Physical sciences, General Physics and Astronomy, [PHYS.COND.CM-SCE]Physics [physics]/Condensed Matter [cond-mat]/Strongly Correlated Electrons [cond-mat.str-el], Physical and Theoretical Chemistry
Abstract

International audience; In this work, we study the Wigner localization of interacting electrons that are confined to a quasi-one-dimensional harmonic potential using accurate quantum chemistry approaches. We demonstrate that the Wigner regime can be reached using small values of the confinement parameter. To obtain physical insight in our results, we analyze them with a semi-analytical model for two electrons. Thanks to electronic-structure properties such as the one-body density and the particle–hole entropy, we are able to define a path that connects the Wigner regime to the Fermi-gas regime by varying the confinement parameter. In particular, we show that the particle–hole entropy, as a function of the confinement parameter, smoothly connects the two regimes. Moreover, it exhibits a maximum that could be interpreted as the transition point between the localized and delocalized regimes.

Published
2022

16. Toward the understanding of water-in-salt electrolytes: Individual ion activities and liquid junction potentials in highly concentrated aqueous solutions

Author

Alexis Grimaud, Nicolas Dubouis, Damien Degoulange, Chimie du solide et de l'énergie (CSE), Collège de France (CdF (institution))-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Réseau sur le stockage électrochimique de l'énergie (RS2E), Université de Picardie Jules Verne (UPJV)-Institut de Chimie du CNRS (INC)-Aix Marseille Université (AMU)-Université de Pau et des Pays de l'Adour (UPPA)-Université de Nantes (UN)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), Université de Nantes (UN)-Aix Marseille Université (AMU)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Université de Picardie Jules Verne (UPJV)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA), and ANR-19-CE05-0014,BALWISE,Batteries aqueuses au Li utilisant des électrolytes superconcentrés(2019)

Subjects
Activity coefficient, Aqueous solution, Chemistry, Inorganic chemistry, Liquid junction potential, General Physics and Astronomy, 02 engineering and technology, Electrolyte, 010402 general chemistry, 021001 nanoscience & nanotechnology, Electrochemistry, 01 natural sciences, Redox, 0104 chemical sciences, Ion, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, symbols.namesake, symbols, Nernst equation, Physical and Theoretical Chemistry, 0210 nano-technology, [CHIM.OTHE]Chemical Sciences/Other
Abstract

Highly concentrated electrolytes were recently proposed to improve the performances of aqueous electrochemical systems by delaying the water splitting and increasing the operating voltage for battery applications. While advances were made regarding their implementation in practical devices, debate exists regarding the physical origin for the delayed water reduction occurring at the electrode/electrolyte interface. Evidently, one difficulty resides in our lack of knowledge regarding ions activity arising from this novel class of electrolyte, it being necessary to estimate the Nernst potential of associated redox reactions such as Li+ intercalation or the hydrogen evolution reaction. In this work, we first measured the potential shift of electrodes selective to either Li+, H+ or Zn2+ ions from diluted to highly concentrated regimes in LiCl or LiTFSI solutions. Observing similar shifts for these different cations and environments, we establish that shifts in redox potentials from diluted to highly concentrated regime originates in large from an increase junction potential, it being dependent on the ions activity coefficients that increase with concentration. While our study shows that single ion activity coefficients, unlike mean ion activity coefficients, cannot be captured by any electrochemical means, we demonstrate that protons concentration increases by approximatively two orders of magnitude from 1 mol.kg-1 to 15-20 mol.kg-1 solutions. Combined with the increased activity coefficients, this increases the activity of protons and thus the pH of highly concentrated solutions which appears acidic.

Published
2021

17. Multi-replica biased sampling for photoswitchable π-conjugated polymers

Author

Mariagrazia Fortino, Concetta Cozza, Adriana Pietropaolo, Massimiliano Bonomi, Università degli Studi 'Magna Graecia' di Catanzaro [Catanzaro, Italie] (UMG), Bioinformatique structurale - Structural Bioinformatics, Centre National de la Recherche Scientifique (CNRS)-Institut Pasteur [Paris], Università degli Studi 'Magna Graecia' di Catanzaro = University of Catanzaro (UMG), and Institut Pasteur [Paris] (IP)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Chemical Physics (physics.chem-ph), Physics, 010304 chemical physics, Metadynamics, FOS: Physical sciences, General Physics and Astronomy, Dihedral angle, 010402 general chemistry, 01 natural sciences, Molecular physics, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, symbols.namesake, Physics - Chemical Physics, Excited state, 0103 physical sciences, symbols, Density functional theory, Emission spectrum, Physical and Theoretical Chemistry, Perturbation theory, Ground state, Hamiltonian (quantum mechanics)
Abstract

In recent years, pi-conjugated polymers are attracting considerable interest in view of their light-dependent torsional reorganization around the pi-conjugated backbone, which determines peculiar light-emitting properties. Motivated by the interest in designing conjugated polymers with tunable photoswitchable pathways, we devised a computational framework to enhance the sampling of the torsional conformational space and at the same time estimate ground to excited-state free-energy differences. This scheme is based on a combination of Hamiltonian Replica Exchange (REM), Parallel Bias metadynamics, and free-energy perturbation theory. In our scheme, each REM replica samples an intermediate unphysical state between the ground and the first two excited states, which are characterized by TD-DFT simulations at the B3LYP/6-31G* level of theory. We applied the method to a 5-mer of 9,9-dioctylfluorene and found that upon irradiation this system can undergo a dihedral inversion from 155 to -155 degrees crossing a barrier that decreases from 0.1 eV in the ground state (S0) to 0.05 eV and 0.04 eV in the first (S1) and second (S2) excited states. Furthermore, S1 and even more S2 were predicted to stabilize coplanar dihedrals, with a local free-energy minimum located at +-44 degrees. The presence of a free-energy barrier of 0.08 eV for the S1 and 0.12 eV for the S2 state can trap this conformation in a basin far from the global free-energy minimum located at 155 degrees. The simulation results were compared with the experimental emission spectrum, showing a quantitative agreement with the predictions provided by our framework., Comment: 14 pages, 6 figures. The present article has been accepted in The Journal of Chemical Physics

Published
2021

18. Kinetic energy released in the vibrational autodetachment of sulfur hexafluoride anion

Author

G. Montagne, S. Martin, Bruno Concina, Christian Bordas, Structure et dynamique multi-échelle des édifices moléculaires (DYNAMO), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Spectrométrie des biomolécules et agrégats (SPECTROBIO), Laboratoire de Spectrométrie Ionique et Moléculaire (LASIM), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon

Subjects
Range (particle radiation), Materials science, 010304 chemical physics, Imaging spectrometer, General Physics and Astronomy, 010402 general chemistry, Kinetic energy, 01 natural sciences, 0104 chemical sciences, Ion, Sulfur hexafluoride, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, chemistry.chemical_compound, Cross section (physics), Microsecond, chemistry, Time windows, 0103 physical sciences, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Physical and Theoretical Chemistry, Atomic physics
Abstract

International audience; The kinetic energy release distribution (KERD) in the vibrational autodetachment (VAD) from sulfur hexafluoride anion SF6- has been measured in a velocity map imaging spectrometer for delays in the range of a few tens of microseconds. The experimental KERD is analyzed within the framework of the detailed-balance: first using the standard Langevin model and subsequently using a more refined and realistic model based on the experimental attachment cross section. A discussion on the processes involved in the attachment and the VAD is presented based on an empirical fit of the attachment cross section. The lifetime derived from the model is in good agreement with the experimental time window, strengthening this theoretical approach for this model system.

Published
2021

19. Reduced variance analysis of molecular dynamics simulations by linear combination of estimators

Author

Daan Frenkel, Benjamin Rotenberg, Samuel W. Coles, Etienne Mangaud, University of Bath [Bath], The Faraday Institution, Laboratoire Modélisation et Simulation Multi-Echelle (MSME), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Gustave Eiffel, University of Cambridge [UK] (CAM), PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), and Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Computation, FOS: Physical sciences, General Physics and Astronomy, Molecular dynamics, 010402 general chemistry, Control variates, Radial distribution function, 01 natural sciences, Classical statistical mechanics, Variational methods, Position (vector), Physics - Chemical Physics, 0103 physical sciences, Computational physics, Statistical physics, Physical and Theoretical Chemistry, Linear combination, Estimation theory, Mathematics, Chemical Physics (physics.chem-ph), Lennard-Jones fluid, 010304 chemical physics, Estimator, Observable, Variance (accounting), 0104 chemical sciences, Transport properties, Molecular simulations, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph]
Abstract

Building upon recent developments of force-based estimators with a reduced variance for the computation of densities, radial distribution functions or local transport properties from molecular simulations, we show that the variance can be further reduced by considering optimal linear combinations of such estimators. This control variates approach, well known in Statistics and already used in other branches of computational Physics, has been comparatively much less exploited in molecular simulations. We illustrate this idea on the radial distribution function and the one-dimensional density of a bulk and confined Lennard-Jones fluid, where the optimal combination of estimators is determined for each distance or position, respectively. In addition to reducing the variance everywhere at virtually no additional cost, this approach cures an artefact of the initial force-based estimators, namely small but non-zero values of the quantities in regions where they should vanish. Beyond the examples considered here, the present work highlights more generally the underexplored potential of control variates to estimate observables from molecular simulations., 4 Pages and 2 Figures

Published
2021

20. The effect of uncertainty on building blocks in molecules

Author

Anthony Scemama, Andreas Savin, Laboratoire de chimie théorique (LCT), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Groupe Méthodes et outils de la chimie quantique (LCPQ) (GMO), Laboratoire de Chimie et Physique Quantiques Laboratoire (LCPQ), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), and Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Chemical Physics (physics.chem-ph), atoms, Physics - Chemical Physics, probabilities, FOS: Physical sciences, General Physics and Astronomy, chemical bond, Physical and Theoretical Chemistry, effective number of electrons
Abstract

International audience; Probabilities to find a chosen number of electrons in flexible domains of space are calculated for highly correlated wave functions. Quantum mechanics can produce higher probabilities for chemically relevant arrangements of electrons in these regions. However, the probability to have a given arrangement, e.g., that corresponding to chemical formulas (bonds or atoms), is low in spite of often being maximal. Like in valence bond theory, it is useful to consider alternative distributions of the electrons. Exchanges of electrons should be considered not only between atoms, but also between other types of regions, like those attributed to lone pairs. It is useful to have definitions flexible enough to allow the user to find the reference representations he considers most relevant. We tentatively suggest a tool (the effective number of parties) to help one make the choice.

Published
2022

21. Role of torsional potential in chain conformation, thermodynamics, and glass formation of simulated polybutadiene melts

Author

F. Demydiuk, M. Solar, H. Meyer, O. Benzerara, W. Paul, J. Baschnagel, Institut Charles Sadron (ICS), Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Martin-Luther-Universität Halle Wittenberg (MLU), and Meyer, Hendrik

Subjects
[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, [CHIM.POLY] Chemical Sciences/Polymers, [CHIM.THEO] Chemical Sciences/Theoretical and/or physical chemistry, [CHIM.POLY]Chemical Sciences/Polymers, General Physics and Astronomy, Physical and Theoretical Chemistry, [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft], [PHYS.COND.CM-SCM] Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft]
Abstract

For polymer chains, the torsional potential is an important intramolecular energy influencing chain flexibility and segmental dynamics. Through molecular dynamics simulations of an atomistic model for melts of cis– trans-1,4-polybutadiene (PBD), we explore the effect of the torsions on conformational properties (bond vector correlations and mean-square internal distances), fundamental thermodynamic quantities (density, compressibility, internal energy, and specific heat), and glass transition temperature Tg. This is achieved by systematically reducing the strength of the torsional potential, starting from the chemically realistic chain (CRC) model with the full potential toward the freely rotating chain (FRC) model without the torsional potential. For the equilibrium liquid, we find that the effect of the torsions on polymer conformations is very weak. Still weaker is the influence on the monomer density ρ and isothermal compressibility κ T of the polymer liquid, both of which can be considered as independent of the torsional potential. We show that a van der Waals-like model proposed by Long and Lequeux [Eur. Phys. J. E 4, 371 (2001)] allows us to describe very well the temperature ( T) dependence of ρ and κ T. We also find that our data obey the linear relation between [Formula: see text] and 1/ T (with the Boltzmann constant kB) that has recently been predicted and verified on the experiment by Mirigian and Schweizer [J. Chem. Phys. 140, 194507 (2014)]. For the equilibrium liquid, simulations result in a specific heat, at constant pressure and at constant volume, which increases on cooling. This T dependence is opposite to the one found experimentally for many polymer liquids, including PBD. We suggest that this difference between simulation and experiment may be attributed to quantum effects due to hydrogen atoms and backbone vibrations, which, by construction, are not included in the classical united-atom model employed here. Finally, we also determine Tg from the density–temperature curve monitored in a finite-rate cooling process. While the influence of the torsional potential on ρ( T) is vanishingly small in the equilibrium liquid, the effect of the torsions on Tg is large. We find that Tg decreases by about 150 K when going from the CRC to the FRC model.

Published
2022

22. Assessing the sequence dependence of pyrimidine-pyrimidone (6-4) photoproduct in a duplex double-stranded DNA: A pitfall for microsecond range simulation

Author

Alessio Bartocci, Natacha Gillet, Elise Dumont, Laboratoire de Chimie - UMR5182 (LC), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)-Institut de Chimie du CNRS (INC)

Subjects
Pyrimidine, Sequence dependence, General Physics and Astronomy, Pyrimidinones, Molecular Dynamics Simulation, 010402 general chemistry, 01 natural sciences, chemistry.chemical_compound, Molecular dynamics, 0103 physical sciences, Pyrimidone, Physical and Theoretical Chemistry, ComputingMilieux_MISCELLANEOUS, 010304 chemical physics, Chemistry, DNA, Photochemical Processes, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Microsecond, Pyrimidines, Covalent bond, Duplex (building), Biophysics, Nucleic Acid Conformation, Double stranded
Abstract

Sequence dependence of the (6–4) photoproduct conformational landscape when embedded in six 25-bp duplexes is evaluated along extensive unbiased and enhanced (replica exchange with solute tempering, REST2) molecular dynamics simulations. The structural reorganization as the central pyrimidines become covalently tethered is traced back in terms of non-covalent interactions, DNA bending, and extrusion of adenines of the opposite strands. The close sequence pattern impacts the conformational landscape around the lesion, inducing different upstream and downstream flexibilities. Moreover, REST2 simulations allow us to probe structures possibly important for damaged DNA recognition.

Published
2021

23. A quantum optics approach to photoinduced electron transfer in cavities

Author

Guido Pupillo, Johannes Schachenmayer, David Wellnitz, Schachenmayer, Johannes, Institut de Science et d'ingénierie supramoléculaires (ISIS), Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, and Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)

Subjects
Photon, General Physics and Astronomy, FOS: Physical sciences, 010402 general chemistry, 01 natural sciences, Photoinduced electron transfer, [PHYS.PHYS.PHYS-CHEM-PH] Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Electron transfer, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], Physics - Chemical Physics, 0103 physical sciences, Master equation, Physical and Theoretical Chemistry, [PHYS.QPHY] Physics [physics]/Quantum Physics [quant-ph], Physics, Quantum optics, Chemical Physics (physics.chem-ph), Quantum Physics, 010304 chemical physics, Rate equation, 0104 chemical sciences, Dissipative system, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Atomic physics, Ground state, Quantum Physics (quant-ph)
Abstract

We study a simple model for photoinduced electron transfer reactions for the case of many donor-acceptor pairs that are collectively and homogeneously coupled to a photon mode of a cavity. We describe both coherent and dissipative collective effects resulting from this coupling within the framework of a quantum optics Lindblad master equation. We introduce a method to derive an effective rate equation for electron transfer, by adiabatically eliminating donor and acceptor states and the cavity mode. The resulting rate equation is valid both for weak and strong coupling to the cavity mode, and describes electronic transfer through both the cavity coupled bright states and the uncoupled dark states. We derive an analytic expression for the instantaneous electron transfer rate that depends non-trivially on the time-varying number of pairs in the ground state. We find that under proper resonance conditions, and in the presence of an incoherent drive, reaction rates can be enhanced by the cavity. This enhancement persists, and can even be largest, in the weak light-matter coupling regime. We discuss how the cavity effect is relevant for realistic experiments., 17 pages, 5 figures

Published
2021

24. Radiative relaxation in isolated large carbon clusters: Vibrational emission versus recurrent fluorescence

Author

O. Lacinbala, F. Calvo, C. Dubosq, C. Falvo, P. Parneix, M. Rapacioli, A. Simon, T. Pino, Institut des Sciences Moléculaires d'Orsay (ISMO), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire Interdisciplinaire de Physique [Saint Martin d’Hères] (LIPhy ), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Modélisation, Agrégats, Dynamique (LCPQ) (MAD), Laboratoire de Chimie et Physique Quantiques Laboratoire (LCPQ), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), and ANR-16-CE29-0025,PACHYNO,Caracterisation de la diversité de nanoparticules de carbone et d'hydrogène d'intérêt astrophysique.(2016)

Subjects
[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, General Physics and Astronomy, Astrophysics::Cosmology and Extragalactic Astrophysics, Physical and Theoretical Chemistry, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics
Abstract

Recurrent fluorescence (RF) from isolated carbon clusters containing between 24 and 60 atoms is theoretically investigated as a function of internal energy, cluster size, and structural features. The vibrational relaxation kinetics and the associated IR emission spectra are determined by means of a Monte Carlo approach with vibrational density of states computed in the harmonic approximation. RF is generally found to be highly competitive with vibrational emission. The behaviors predicted for clusters of various sizes and archetypal structures indicate that the IR emission spectra are strongly influenced by RF, an energy gap law being obtained for the evolution of the RF rate constant depending on the electronic excitation state. The present results are relevant to the photophysics of the interstellar medium and could contribute to elucidating the carriers of the extended red emission bands and the continuum emission lying below the aromatic infrared bands believed to originate from mixed aromatic–aliphatic compounds.

Published
2022

25. Behaviors of sodium and calcium ions at the borosilicate glass–water interface: Gaining new insights through an ab initio molecular dynamics study

Author

Hicham Jabraoui, Thibault Charpentier, Stéphane Gin, Jean-Marc Delaye, Rodolphe Pollet, Laboratoire Structure et Dynamique par Résonance Magnétique (LCF) (LSDRM), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Département de recherche sur les Procédés et Matériaux pour les Environnements complexes (DPME), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Programmes Transversaux de Compétences 'Simulation Numérique' (ALTERVER) of the French Alternative Energies and Atomic Energy Commission (CEA), and HPC/AI resources of TGCC under Allocation No. 2021-A0100810825 made by GENCI

Subjects
General Physics and Astronomy, [CHIM.MATE]Chemical Sciences/Material chemistry, Physical and Theoretical Chemistry
Abstract

We study reactivity and leaching at the calcium sodium borosilicate (CNBS)–water interface by means of a Car–Parrinello ab initio molecular dynamics simulation over a simulation time of 100 ps. With an emphasis on the comparison between the behaviors of Ca2+ and Na+ cations at the CNBS glass–water interface, different mechanism events during the trajectory are revealed, discussed, and correlated with other density functional theory calculations. We show that Na+ ions can be released in solution, while Ca2+ cannot leave the surface of CNBS glass. This release is correlated with the vacancy energy of Ca2+ and Na+ cations. Here, we found that the CNBS structure with the Na+ cation vacancy is energetically more favorable than the structure with the Ca2+ cation vacancy. The calcium adsorption site has been shown to have a greater affinity for water than can be found in the case of the sodium site, demonstrating that affinity may not be considered a major factor controlling the release of cations from the glass to the solution.

Published
2022

26. Vibronic fingerprints in the luminescence of graphene quantum dots at cryogenic temperature

Author

Thomas Liu, Baptiste Carles, Christine Elias, Claire Tonnelé, Daniel Medina-Lopez, Akimitsu Narita, Yannick Chassagneux, Christophe Voisin, David Beljonne, Stéphane Campidelli, Loïc Rondin, Jean-Sébastien Lauret, Laboratoire Lumière, Matière et Interfaces (LuMIn), CentraleSupélec-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Ecole Normale Supérieure Paris-Saclay (ENS Paris Saclay), Nano Optique et Spectroscopy (NOOS), CentraleSupélec-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Ecole Normale Supérieure Paris-Saclay (ENS Paris Saclay)-CentraleSupélec-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Ecole Normale Supérieure Paris-Saclay (ENS Paris Saclay), Université de Mons (UMons), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN UMR 3685), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Polymerforschung (MPI-P), Max-Planck-Gesellschaft, Laboratoire de physique de l'ENS - ENS Paris (LPENS), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), and ANR-19-CE09-0031,GRANAO,Boites quantiques et Nanorubans de Graphene pour l'optique(2019)

Subjects
[PHYS]Physics [physics], [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], General Physics and Astronomy, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], Physics::Chemical Physics, Physical and Theoretical Chemistry
Abstract

Atomically precise graphene quantum dots synthesized by bottom-up chemistry are promising versatile single emitters with potential applications for quantum photonic technologies. Toward a better understanding and control of graphene quantum dot (GQD) optical properties, we report on single-molecule spectroscopy at cryogenic temperature. We investigate the effect of temperature on the GQDs’ spectral linewidth and vibronic replica, which we interpret building on density functional theory calculations. Finally, we highlight that the vibronic signatures are specific to the GQD geometry and can be used as a fingerprint for identification purposes.

Published
2022

27. Manipulating the physical states of confined ibuprofen in SBA-15 based drug delivery systems obtained by solid-state loading: Impact of the loading degree

Author

Jérémy Dhainaut, Carmen Ciotonea, Nicolas Tabary, Sébastien Royer, Benjamin Malfait, Natália T. Correia, Jean-Philippe Dacquin, Yannick Guinet, Alain Hédoux, Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Unité Matériaux et Transformations - UMR 8207 (UMET), Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Unité de Catalyse et Chimie du Solide - UMR 8181 (UCCS), Université d'Artois (UA)-Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Université de Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, Unité Matériaux et Transformations (UMET) - UMR 8207, Institut de Physique de Rennes [IPR], Unité de Catalyse et Chimie du Solide (UCCS) - UMR 8181, Unité Matériaux et Transformations - UMR 8207 [UMET], Unité de Catalyse et Chimie du Solide - UMR 8181 [UCCS], Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Ecole Nationale Supérieure de Chimie de Lille (ENSCL)-Institut National de la Recherche Agronomique (INRA), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Unité de Catalyse et de Chimie du Solide - UMR 8181 (UCCS), Université d'Artois (UA)-Ecole Centrale de Lille-Ecole Nationale Supérieure de Chimie de Lille (ENSCL)-Centre National de la Recherche Scientifique (CNRS)-Université de Lille, Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centrale Lille Institut (CLIL), and Centrale Lille Institut (CLIL)-Université d'Artois (UA)-Centrale Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Lille

Subjects
Diffraction, Materials science, General Physics and Astronomy, Ibuprofen, 010402 general chemistry, 01 natural sciences, law.invention, Matrix (chemical analysis), Differential scanning calorimetry, Drug Delivery Systems, law, 0103 physical sciences, Monolayer, Molecule, Amorphous materials, Bioavailability, Mesoporous material, Nanomarterials, Dug delivery, Thermogravimetric analysis, Glass transitions, Raman spectral imaging, Nanocrystals, Low-wavenumber Raman mapping, Physical and Theoretical Chemistry, Crystallization, sustained release, loading degree, 010304 chemical physics, physical state, Anti-Inflammatory Agents, Non-Steroidal, [CHIM.CATA]Chemical Sciences/Catalysis, Silicon Dioxide, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, [SDV.SP.PG]Life Sciences [q-bio]/Pharmaceutical sciences/Galenic pharmacology, Chemical engineering, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Crystallite, Glass transition, bioavailability, Confinement
Abstract

International audience; Using the Milling-Assisted Loading (MAL) solid-state method for loading a poorly water-soluble drug (ibuprofen, IBP) within the SBA-15 matrix has given the opportunity to manipulate the physical state of drugs for optimizing bioavailability. The MAL method makes it easy to control and analyze the influence of the degree of loading on the physical state of IBP inside the SBA-15 matrix with an average pore diameter of 9.4 nm. It was found that the density of IBP molecules in an average pore size has a direct influence on both the glass transition and the mechanism of crystallization. Detailed analyzes of the crystallite distribution and melting by Raman mapping, x-ray diffraction, and differential scanning calorimetry have shown that the crystals are localized in the core of the channel and surrounded by a liquid monolayer. The results of these complementary investigations have been used for determining the relevant parameters (related to the SBA-15 matrix and to the IBP molecule) and the nature of the physical state of the confined matter.

Published
2020

28. Energy transport and light propagation mechanisms in organic single crystals

Author

Sajedeh Motamen, Guenter Reiter, Françoise Serein-Spirau, L. Simon, Richard Hildner, Stephan Wiesneth, Bernd Wittmann, Optical spectroscopy of functional nanosystems, Institut de Science des Matériaux de Mulhouse (IS2M), Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Institut de chimie des surfaces et interfaces de Mulhouse (ICSIM), and Ecole Nationale Supérieure de Chimie de Mulhouse-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Photoluminescence, Organic single crystal, Exciton, Population, Optical spectroscopy, General Physics and Astronomy, 010402 general chemistry, 01 natural sciences, Fluence, Molecular physics, waveguiding, 0103 physical sciences, Physical and Theoretical Chemistry, Diffusion (business), [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], education, education.field_of_study, Annihilation, 010304 chemical physics, Time-resolved fluorescence, Nanosecond, 0104 chemical sciences, Energy transport, photon recycling, Excitation
Abstract

Unambiguous information about spatiotemporal exciton dynamics in three-dimensional nanometer- to micrometer-sized organic structures is difficult to obtain experimentally. Exciton dynamics can be modified by annihilation processes, and different light propagation mechanisms can take place, such as active waveguiding and photon recycling. Since these various processes and mechanisms can lead to similar spectroscopic and microscopic signatures on comparable time scales, their discrimination is highly demanding. Here, we study individual organic single crystals grown from thiophene-based oligomers. We use time-resolved detection-beam scanning microscopy to excite a local singlet exciton population and monitor the subsequent broadening of the photoluminescence (PL) signal in space and on pico- to nanosecond time scales. Combined with Monte Carlo simulations, we were able to exclude photon recycling for our system, whereas leakage radiation upon active waveguiding leads to an apparent PL broadening of about 20% compared to the initial excitation profile. Exciton-exciton annihilation becomes important at high excitation fluence and apparently accelerates the exciton dynamics leading to apparently increased diffusion lengths. At low excitation fluences, the spatiotemporal PL broadening results from singlet exciton diffusion with diffusion lengths of up to 210 nm. Surprisingly, even in structurally highly ordered single crystals, the transport dynamics is subdiffusive and shows variations between different crystals, which we relate to varying degrees of static and dynamic electronic disorders.

Published
2020

29. Computation and analysis of bound vibrational spectra of the neon tetramer using row orthonormal hyperspherical coordinates

Author

Bruno Lepetit, Théorie (LCAR), Laboratoire Collisions Agrégats Réactivité (LCAR), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse)

Subjects
[PHYS]Physics [physics], Physics, 010304 chemical physics, Computation, General Physics and Astronomy, chemistry.chemical_element, 010402 general chemistry, 01 natural sciences, Spectral line, 0104 chemical sciences, Neon, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], chemistry, Quantum mechanics, Harmonics, 0103 physical sciences, Physics::Atomic and Molecular Clusters, Orthonormal basis, Configuration space, Physics::Chemical Physics, Physical and Theoretical Chemistry, Wave function, Basis set
Abstract

International audience; The paper presents the first implementation of the row-orthonormal hyperspherical coordinate formalism for the computation of the vibrational spectrum of a tetratomic system. The wavefunc-tion of Ne 4 is expanded on a large basis set of hyperspherical harmonics generated numerically. This method not only provides spectra with reasonable accuracy, but also gives physical insight into the vibrational dynamics of the system. The characteristics of the spectra are related to the symmetry and localization of the wavefunction in configuration space.

Published
2020

30. Water adlayers on noble metal surfaces: Insights from energy decomposition analysis

Author

Clabaut, Paul, Staub, Ruben, Galiana, Joachim, Antonetti, Elise, Steinmann, Stephan N., Steinmann, Stephan, Laboratoire de Chimie - UMR5182 (LC), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)-Institut de Chimie du CNRS (INC)

Subjects
Materials science, 010304 chemical physics, Force field (physics), General Physics and Astronomy, [CHIM.CATA]Chemical Sciences/Catalysis, engineering.material, 010402 general chemistry, Heterogeneous catalysis, 01 natural sciences, 0104 chemical sciences, Metal, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Dipole, Adsorption, Chemical physics, visual_art, 0103 physical sciences, visual_art.visual_art_medium, engineering, Molecule, Noble metal, Density functional theory, Physical and Theoretical Chemistry, Wave function, Polarization (electrochemistry)
Abstract

Water molecules adsorbed on noble metal surfaces are of fundamental interest in surface science, heterogeneous catalysis and as a model for the metal/water interface. Herein, we analyse 27 water structures adsorbed on five noble metal surfaces (Cu, Ag, Au, Pd, Pt) via density functional theory and energy decomposition analysis based on the block localized wave function technique. The structures, ranging from the monomers to ice adlayers, reveal that the charge-transfer from water to the surface is nearly independent from the charge-transfer between the water molecules, while the polarization energies are cooperative. Dense water-water networks with small surface dipoles, such as the sqrt(39) x sqrt(39) unit cell (experimentally observed on Pt(111) ) are favored compared to the highly ordered and popular Hup and Hdown phases. The second main result of our study is that the many-body interactions, which stabilize the water assemblies on the metal surfaces, are dominated by the polarization energies, with the charge-transfer scaling with the polarization energies. Hence, if an empirical model could be found that reproduces the polarization energies, the charge-transfer could be predicted as well, opening exciting perspectives for force field development.

Published
2020

31. Probabilistic performance estimators for computational chemistry methods: Systematic improvement probability and ranking probability matrix. II. Applications

Author

Pascal Pernot, Andreas Savin, Laboratoire de Chimie Physique D'Orsay (LCPO), Université Paris-Sud - Paris 11 (UP11)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de chimie théorique (LCT), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Chemical Physics (physics.chem-ph), 010304 chemical physics, Computer science, Probabilistic logic, Stochastic matrix, Robust statistics, FOS: Physical sciences, General Physics and Astronomy, Experimental data, Estimator, Probability and statistics, Benchmarking, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, Computational chemistry, Physics - Chemical Physics, Physics - Data Analysis, Statistics and Probability, 0103 physical sciences, Physical and Theoretical Chemistry, Data Analysis, Statistics and Probability (physics.data-an), Statistic, ComputingMilieux_MISCELLANEOUS, [PHYS.PHYS.PHYS-DATA-AN]Physics [physics]/Physics [physics]/Data Analysis, Statistics and Probability [physics.data-an]
Abstract

In the first part of this study (Paper I), we introduced the systematic improvement probability (SIP) as a tool to assess the level of improvement on absolute errors to be expected when switching between two computational chemistry methods. We developed also two indicators based on robust statistics to address the uncertainty of ranking in computational chemistry benchmarks: Pinv , the inversion probability between two values of a statistic, and Pr , the ranking probability matrix. In this second part, these indicators are applied to nine data sets extracted from the recent benchmarking literature. We illustrate also how the correlation between the error sets might contain useful information on the benchmark dataset quality, notably when experimental data are used as reference.

Published
2020

32. Studying polymer diffusiophoresis with non-equilibrium molecular dynamics

Author

Simón Ramírez-Hinestrosa, Daan Frenkel, Lydéric Bocquet, Hiroaki Yoshida, Frenkel, Daan [0000-0002-6362-2021], Apollo - University of Cambridge Repository, Micromegas : Nano-Fluidique, Laboratoire de physique de l'ENS - ENS Paris (LPENS (UMR_8023)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Laboratoire de physique de l'ENS - ENS Paris (LPENS), Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Sorbonne Université (SU)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Sorbonne Université (SU)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)

Subjects
Materials science, physics.chem-ph, General Physics and Astronomy, FOS: Physical sciences, Condensed Matter - Soft Condensed Matter, 010402 general chemistry, 01 natural sciences, chemistry.chemical_compound, Molecular dynamics, Diffusiophoresis, Physics - Chemical Physics, 0103 physical sciences, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), cond-mat.mes-hall, Physical and Theoretical Chemistry, chemistry.chemical_classification, Chemical Physics (physics.chem-ph), [PHYS]Physics [physics], cond-mat.soft, Quantitative Biology::Biomolecules, 010304 chemical physics, Solid particle, Condensed Matter - Mesoscale and Nanoscale Physics, Polymer, Computational Physics (physics.comp-ph), 0104 chemical sciences, Condensed Matter::Soft Condensed Matter, Monomer, chemistry, Chemical physics, physics.comp-ph, Soft Condensed Matter (cond-mat.soft), Concentration gradient, Physics - Computational Physics, Hydrodynamic flow
Abstract

International audience; We report a numerical study of the diffusiophoresis of short polymers using non-equilibrium molecular dynamics simulations. More precisely, we consider polymer chains in a fluid containing a solute which has a concentration gradient, and examine the variation of the induced diffusiophoretic velocity of the polymer chains as the interaction between the monomer and the solute is varied. We find that there is a non-monotonic relation between the diffusiophoretic mobility and the strength of the monomer-solute interaction. In addition we find a weak dependence of the mobility on the length of the polymer chain, which shows clear difference from the diffusiophoresis of a solid particle. Interestingly, the hydrodynamic flow through the polymer is much less screened than for pressure driven flows. a) Electronic mail: df246@cam.ac.uk 1 arXiv:1909.06352v2 [cond-mat.soft] 8 Apr 2020 Studying polymer diffusiophoresis with Non-Equilibrium Molecular Dynamics

Published
2020

33. Action spectroscopy of spin forbidden states in the gas phase: A powerful probe for large non-luminescent molecules

Author

M. Briant, C. Pothier, Niloufar Shafizadeh, Floriane Grollau, Marc-André Gaveau, Benoît Soep, Laboratoire Interactions, Dynamiques et Lasers (ex SPAM) (LIDyl), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Moléculaires d'Orsay (ISMO), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], Materials science, 010304 chemical physics, Absorption spectroscopy, General Physics and Astronomy, 010402 general chemistry, 7. Clean energy, 01 natural sciences, Molecular physics, Porphyrin, Spectral line, 0104 chemical sciences, Microsecond, chemistry.chemical_compound, chemistry, 13. Climate action, Excited state, 0103 physical sciences, Atom, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Physical and Theoretical Chemistry, Triplet state, Spectroscopy, ComputingMilieux_MISCELLANEOUS
Abstract

International audience; Triplet action spectra of two similar copper porphyrins, copper Tetraphenylporphyrin (CuTPP) and copper Octaethylporphyrin (CuOEP) have been studied in the gas phase at low temperatures in absence of external perturbations by a resonant pump and a 193 nm probe ionizing the 3 * orbital localized on the porphyrin cycle. The molecules were prepared by laser desorption in a disk source, then cooled in a helium supersonic expansion and finally excited in the Q band system (S1 ← S0). This type of experiment allows the spectroscopic characterization of large non luminescent molecules in absence of solvent perturbations. The two copper porphyrins exhibit a broad electronic origin Q00 absorption spectrum, partly caused by the short lifetime of the excited (S1) state. The two porphyrins differ strongly with a strong Q00 band for CuOEP and a weak one for CuTPP, in agreement with M. Gouterman's 4 orbital model. Also, the two molecules exhibit different solvent shifts: CuOEP is blue shifted in non polar solvents owing to its alkyl substituents, while CuTPP is red shifted as for regular transitions to * orbitals. The decay dynamics of the triplet state exhibit a collision free lifetime of 70±7 ns for CuTPP atop a microsecond decay. This non exponential decay can be viewed as an evidence of time evolution of two states combining: the state with spin 1 borne by the porphyrin ring and that by the Cu atom, ½. Therefore, this method allows solvent free spectrodynamics of large molecules in the short microsecond time range.

Published
2020

34. Hydration free energies and solvation structures with molecular density functional theory in the hypernetted chain approximation

Author

Sohvi Luukkonen, Luc Belloni, Maximilien Levesque, Daniel Borgis, Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Processus d'Activation Sélective par Transfert d'Energie Uni-électronique ou Radiatif (UMR 8640) (PASTEUR), Département de Chimie - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire (LIONS), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)

Subjects
[PHYS]Physics [physics], Physics, Quantitative Biology::Biomolecules, 010304 chemical physics, Solvation, General Physics and Astronomy, Thermodynamics, 010402 general chemistry, Electrostatics, 01 natural sciences, Integral equation, Force field (chemistry), 0104 chemical sciences, Ion, 0103 physical sciences, [CHIM]Chemical Sciences, Molecule, Molecular Density, [INFO]Computer Science [cs], Free energies, Physics::Chemical Physics, Physical and Theoretical Chemistry
Abstract

The capability of molecular density functional theory in its lowest, second-order approximation, equivalent to the hypernetted chain approximation in integral equations, to predict accurately the hydration free-energies and microscopic structure of molecular solutes is explored for a variety of systems: spherical hydrophobic solutes, ions, water as a solute, and the Mobley’s dataset of organic molecules. The successes and the caveats of the approach are carefully pinpointed. Compared to molecular simulations with the same force field and the same fixed solute geometries, the theory describes accurately the solvation of cations, less so that of anions or generally H-bond acceptors. Overall, the electrostatic contribution to solvation free-energies of neutral molecules is correctly reproduced. On the other hand, the cavity contribution is poorly described but can be corrected using scaled-particle theory ideas. Addition of a physically motivated, one-parameter cavity correction accounting for both pressure and surface effects in the nonpolar solvation contribution yields a precision of 0.8 kcal/mol for the overall hydration free energies of the whole Mobley’s dataset. Inclusion of another one-parameter cavity correction for the electrostatics brings it to 0.6 kcal/mol, that is, kBT. This is accomplished with a three-orders of magnitude numerical speed-up with respect to molecular simulations.The capability of molecular density functional theory in its lowest, second-order approximation, equivalent to the hypernetted chain approximation in integral equations, to predict accurately the hydration free-energies and microscopic structure of molecular solutes is explored for a variety of systems: spherical hydrophobic solutes, ions, water as a solute, and the Mobley’s dataset of organic molecules. The successes and the caveats of the approach are carefully pinpointed. Compared to molecular simulations with the same force field and the same fixed solute geometries, the theory describes accurately the solvation of cations, less so that of anions or generally H-bond acceptors. Overall, the electrostatic contribution to solvation free-energies of neutral molecules is correctly reproduced. On the other hand, the cavity contribution is poorly described but can be corrected using scaled-particle theory ideas. Addition of a physically motivated, one-parameter cavity correction accounting for both pressure ...

Published
2020

35. How methane hydrate recovers at very high pressure the hexagonal ice structure

Author

Ph. Depondt, Fabio Pietrucci, Sofiane Schaack, M. Moog, Fabio Finocchi, Institut des Nanosciences de Paris (INSP), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Oxydes en basses dimensions (INSP-E9), and Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Phase transition, Materials science, Hydrogen, General Physics and Astronomy, chemistry.chemical_element, 010402 general chemistry, 01 natural sciences, 7. Clean energy, Methane, chemistry.chemical_compound, Methane Hydrate, Phase (matter), 0103 physical sciences, Path integral molecular dynamics, Physics::Chemical Physics, Physical and Theoretical Chemistry, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], [PHYS]Physics [physics], 010304 chemical physics, Metadynamics, High pressures, 0104 chemical sciences, Nuclear Quantum Effects, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, chemistry, Chemical physics, Phase transitions, [SDU]Sciences of the Universe [physics], Ab initio, Hydrate, Ambient pressure
Abstract

International audience; Methane hydrate was recently shown, both experimentally and through simulations, to be stable up to the remarkably high pressure of 150 GPa. A new methane hydrate high-pressure (MH-IV) phase, reminiscent of ice at ambient pressure, was described for pressures above approximately 40 GPa. We disentangle here the main contributions to the relative stability of the lower pressure, denoted MH-III and the high-pressure MH-IV structures. Through several simulation techniques, including metadynamics and Path Integral Molecular Dynamics for nuclear quantum effects, we analyze the phase transition mechanism, which implies hydrogen bond breaking and reforming, as well as methane reordering. The transition pathway is far from trivial and the quantum delocalization of the hydrogen nuclei plays a significant role.

Published
2020

36. Comparison of time reversal symmetric and asymmetric nano-swimmers oriented with an electric field in soft matter

Author

Victor Teboul, D. Poulet, M. Bruneau, Gabriel Rajonson, Université de Technologie de Compiègne (UTC), Laboratoire de Photonique d'Angers (LPHIA), Université d'Angers (UA), MOLTECH-Anjou, Université d'Angers (UA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Propriétés Optiques des Matériaux et Applications (POMA), Centre National de la Recherche Scientifique (CNRS)-Université d'Angers (UA), University of California [Berkeley], and University of California

Subjects
Field (physics), FOS: Physical sciences, General Physics and Astronomy, Motion (geometry), Condensed Matter - Soft Condensed Matter, 010402 general chemistry, 01 natural sciences, Displacement (vector), Quantitative Biology::Cell Behavior, Quantitative Biology::Subcellular Processes, Molecular dynamics, Electric field, 0103 physical sciences, Molecular motor, [PHYS.COND.CM-DS-NN]Physics [physics]/Condensed Matter [cond-mat]/Disordered Systems and Neural Networks [cond-mat.dis-nn], Soft matter, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], Physical and Theoretical Chemistry, ComputingMilieux_MISCELLANEOUS, Brownian motion, Physics, Physics::Biological Physics, 010304 chemical physics, Disordered Systems and Neural Networks (cond-mat.dis-nn), Condensed Matter - Disordered Systems and Neural Networks, 0104 chemical sciences, Classical mechanics, Soft Condensed Matter (cond-mat.soft), [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft]
Abstract

Using molecular dynamics simulations, we compare the motion of a nanoswimmer based on Purcell’s suggested motor with a time asymmetrical cycle with the motion of the same molecular motor with a time symmetrical cycle. We show that Purcell’s theorem still holds at the nanoscale, despite the local structure and the medium’s fluctuations. Then, with the purpose of both orienting the swimmer’s displacement and increasing the breakdown of the theorem, we study the effect of an electric field on a polarized version of these swimmers. For small and large fields, the time asymmetrical swimmer is more efficient, as suggested by Purcell. However, we find a field range for which Purcell’s theorem is broken for the time symmetric motor. Results suggest that the breakdown of the theorem arises from the competition of the orientation field and Brownian forces, while for larger fields, the field destroys the effect of fluctuations restoring the theorem.Using molecular dynamics simulations, we compare the motion of a nanoswimmer based on Purcell’s suggested motor with a time asymmetrical cycle with the motion of the same molecular motor with a time symmetrical cycle. We show that Purcell’s theorem still holds at the nanoscale, despite the local structure and the medium’s fluctuations. Then, with the purpose of both orienting the swimmer’s displacement and increasing the breakdown of the theorem, we study the effect of an electric field on a polarized version of these swimmers. For small and large fields, the time asymmetrical swimmer is more efficient, as suggested by Purcell. However, we find a field range for which Purcell’s theorem is broken for the time symmetric motor. Results suggest that the breakdown of the theorem arises from the competition of the orientation field and Brownian forces, while for larger fields, the field destroys the effect of fluctuations restoring the theorem.

Published
2020

37. Indirect NMR detection via proton of nuclei subject to large anisotropic interactions, such as 14N, 195Pt, and 35Cl, using the T-HMQC sequence

Author

Racha Bayzou, Julien Trébosc, Ivan Hung, Zhehong Gan, Olivier Lafon, Jean-Paul Amoureux, Université de Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, Unité de Catalyse et Chimie du Solide - UMR 8181 [UCCS], Université de Lille, Sciences et Technologies, National High Magnetic Field Laboratory [NHMFL], Unité de Catalyse et Chimie du Solide (UCCS) - UMR 8181, Bruker, Unité de Catalyse et Chimie du Solide - UMR 8181 (UCCS), Université d'Artois (UA)-Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Institut Michel Eugène Chevreul - FR 2638 (IMEC), Université d'Artois (UA)-Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), National High Magnetic Field Laboratory (NHMFL), Florida State University [Tallahassee] (FSU), and ANR-18-CE08-0015,ThinGlass,Amélioration raisonnée de la conductivité des films minces de LiPON en élucidant leur structure à l'échelle atomique(2018)

Subjects
[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, General Physics and Astronomy, Physical and Theoretical Chemistry
Abstract

International audience; Recently, the T-hetero-nuclear multiple quantum coherence (T-HMQC) sequence using the TRAPDOR (transfer of population in double resonance) recoupling has been introduced for the indirect detection via protons of quadrupolar nuclei with spin I = 1 (14N) or 3/2 (35Cl) in solids at fast magic-angle spinning (MAS). The sequence is simple as it only uses four rectangular pulses and exhibits low t1-noise because the recoupling pulses are applied to the indirectly detected isotope, I. We demonstrate that this sequence is applicable for the detection via protons of spin-1/2 nuclei subject to large chemical shift anisotropy, such as 195Pt. We also report the proton detection of double-quantum (2Q) coherences of 14N nuclei using this sequence. This 2Q version is more robust to the adjustment of the magic angle and the instabilities of the MAS frequencies than its parent single-quantum (1Q) version since the 2Q coherences are not broadened by the first-order quadrupole interaction. In practice, than its 1Q counterpart for the indirect detection of 14N nuclei, the 2Q variant benefits from a slightly higher resolution and comparable sensitivity. In this article, we derive for the first time the Hamiltonian that describes the spin dynamics during the TRAPDOR recoupling. This Hamiltonian demonstrates the importance of the adiabaticity parameter as well as the role of third-order terms in the effective Hamiltonian. The effects of offsets, radio-frequency field, and recoupling time on the efficiency of the T-HMQC sequence are analyzed numerically as well as with experimental detection via protons of 195Pt nuclei in a mixture of cis- and trans-platin and that of 14N and 35Cl isotopes in l-histidine HCl.

Published
2022

38. Enhanced local viscosity around colloidal nanoparticles probed by equilibrium molecular dynamics simulations

Author

Ali Rajabpour, Samy Merabia, Laurent Joly, Mohammad Hassan Saidi, Reza Rabani, Sharif University of Technology [Tehran] (SUT), Modélisation de la matière condensée et des interfaces (MMCI), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), and Imam Khomeini International University (IKIU)

Subjects
Materials science, Diffusion, FOS: Physical sciences, General Physics and Astronomy, Nanoparticle, 02 engineering and technology, Condensed Matter - Soft Condensed Matter, Molecular dynamics, 010402 general chemistry, 01 natural sciences, Slip (ceramics), Physics::Fluid Dynamics, Metal, [SPI]Engineering Sciences [physics], Viscosity, Nanofluid, Physical and Theoretical Chemistry, Diffusion coefficient, [PHYS]Physics [physics], Condensed Matter - Materials Science, Range (particle radiation), Nanofluidics, Materials Science (cond-mat.mtrl-sci), 021001 nanoscience & nanotechnology, 0104 chemical sciences, Chemical physics, visual_art, visual_art.visual_art_medium, Nanoparticles, Soft Condensed Matter (cond-mat.soft), 0210 nano-technology
Abstract

Nanofluids-dispersions of nanometer-sized particles in a liquid medium-have been proposed for a wide variety of thermal management applications. It is known that a solid-like nanolayer of liquid of typical thicknesses of 0.5-1 nm surrounding the colloidal nanoparticles can act as a thermal bridge between the nanoparticle and the bulk liquid. Yet, its effect on the nanofluid viscosity has not been elucidated so far. In this article, we compute the local viscosity of the nanolayer using equilibrium molecular dynamics based on the Green-Kubo formula. We first assess the validity of the method to predict the viscosity locally. We apply this methodology to the calculation of the local viscosity in the immediate vicinity of a metallic nanoparticle for a wide range of solid-liquid interaction strength, where a nanolayer of thickness 1 nm is observed as a result of the interaction with the nanoparticle. The viscosity of the nanolayer, which is found to be higher than its corresponding bulk value, is directly dependent on the solid-liquid interaction strength. We discuss the origin of this viscosity enhancement and show that the liquid density increment alone cannot explain the values of the viscosity observed. Rather, we suggest that the solid-like structure of the distribution of the liquid atoms in the vicinity of the nanoparticle contributes to the nanolayer viscosity enhancement. Finally, we observe a failure of the Stokes-Einstein relation between viscosity and diffusion close to the wall, depending on the liquid-solid interaction strength, which we rationalize in terms of the hydrodynamic slip.

Published
2021

39. Extraction of giant Dzyaloshinskii–Moriya interaction from ab initio calculations: First-order spin–orbit coupling model and methodological study

Author

Rémi Maurice, Mohammed Amine Bouammali, Nicolas Suaud, Nathalie Guihéry, Systèmes étendus et magnétisme (LCPQ) (SEM), Laboratoire de Chimie et Physique Quantiques Laboratoire (LCPQ), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique subatomique et des technologies associées (SUBATECH), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie et Physique Quantiques (LCPQ), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)

Subjects
Physics, 010304 chemical physics, Operator (physics), Ab initio, General Physics and Astronomy, Spin–orbit interaction, 010402 general chemistry, 01 natural sciences, [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], 0104 chemical sciences, Coupling (physics), Amplitude, Ab initio quantum chemistry methods, Quantum mechanics, 0103 physical sciences, Condensed Matter::Strongly Correlated Electrons, Physical and Theoretical Chemistry, Anisotropy, Spin-½
Abstract

International audience; The Dzyaloshinskii–Moriya interaction is expected to be at the origin of interesting magnetic properties, such as multiferroicity, skyrmionic states, and exotic spin orders. Despite this, its theoretical determination is far from being established, neither from the point of view of ab initio methodologies nor from that of the extraction technique to be used afterward. Recently, a very efficient way to increase its amplitude has been demonstrated near the first-order spin–orbit coupling regime. Within the first-order regime, the anisotropic spin Hamiltonian involving the Dzyaloshinskii–Moriya operator becomes inappropriate. Nevertheless, in order to approach this regime and identify the spin Hamiltonian limitations, it is necessary to characterize the underlying physics. To this end, we have developed a simple electronic and spin–orbit model describing the first-order regime and used ab initio calculations to conduct a thorough methodological study.

Published
2021

40. Phenyl argentate aggregates [AgnPhn+1]− (n = 2–8): Models for the self-assembly of atom-precise polynuclear organometallics

Author

Antonija Mravak, Marjan Krstić, Rodolphe Antoine, Sebastian Weske, Alexander Kulesza, Vlasta Bonačić-Koutecký, Richard A. J. O'Hair, Konrad Koszinowski, Steven F. Daly, Philippe Dugourd, Spectrométrie des biomolécules et agrégats (SPECTROBIO), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Institute for Organic and Biomolecular Chemistry, Georg-August-University = Georg-August-Universität Göttingen, Center of Excellence for Science and Technnology - Integration of mediterranean region (STIM), University of Split, Interdisciplinary Center for Advanced Sciences and Technology (ICAST), Humboldt University Of Berlin, Bio21 Molecular Science & Biotechnology Institute [Melbourne] (School of Chemistry), Faculty of Science [Melbourne], University of Melbourne-University of Melbourne, European Project, Georg-August-University [Göttingen], and Humboldt University of Berlin

Subjects
Action spectroscopy, Silver, Photodissociation, Silver cyanide, Photochemistry, Electrospray ionization, Optical spectroscopy, General Physics and Astronomy, Gas phase, 010402 general chemistry, 01 natural sciences, Metal, [SPI]Engineering Sciences [physics], chemistry.chemical_compound, Transmetalation, Absorption spectroscopy, 0103 physical sciences, Bathochromic shift, Cluster (physics), [CHIM]Chemical Sciences, Ion-trap, Physical and Theoretical Chemistry, [PHYS]Physics [physics], Mass spectrometry, 010304 chemical physics, Superatom, UVPD, organometallic oligomers, DFT, 0104 chemical sciences, Crystallography, chemistry, visual_art, visual_art.visual_art_medium
Abstract

International audience; Electrospray ionization of phenyl argentates formed by transmetalation reactions between phenyl lithium and silver cyanide provides access to the argentate aggregates, [AgnPhn+1]−, which were individually mass-selected for n = 2–8 in order to generate their gas-phase Ultraviolet Photodissociation (UVPD) “action” spectra over the range 304–399 nm. A strong bathochromic shift in optical spectra was observed with increasing size/n. Theoretical calculations allowed the assignment of the experimental UVPD spectra to specific isomer(s) and provided crucial insights into the transition from the 2D to 3D structure of the metallic component with the increasing size of the complex. The [AgnPhn+1]− aggregates contain neither pronounced metallic cluster properties nor ligated metallic cluster features and are thus not superatom complexes. They therefore represent novel organometallic characteristics built from Ag2Ph subunits.

Published
2021

41. Tuning the solvation of indigo in aqueous deep eutectics

Author

Pádua, Agílio, Hammond, Oliver, Simon, Guillaume, Gomes, Margarida Costa, Costa Gomes, Margarida, Laboratoire de Chimie - UMR5182 (LC), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)-Institut de Chimie du CNRS (INC), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and ANR-16-IDEX-0005,IDEXLYON,IDEXLYON(2016)

Subjects
chemistry.chemical_classification, Aqueous solution, 010304 chemical physics, Inorganic chemistry, Solvation, General Physics and Astronomy, Indigo dye, 010402 general chemistry, Mole fraction, 01 natural sciences, Indigo, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, chemistry.chemical_compound, [CHIM.GENI]Chemical Sciences/Chemical engineering, chemistry, 0103 physical sciences, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Physical and Theoretical Chemistry, Solubility, ComputingMilieux_MISCELLANEOUS, Alkyl, Choline chloride
Abstract

The solubility of synthetic indigo dye was measured at room temperature in three deep eutectic solvents (DESs)—1:3 choline chloride:1,4-butanediol, 1:3 tetrabutylammonium bromide:1,4-butanediol, and 1:2 choline chloride:p-cresol—to test the hypothesis that the structure of DESs can be systematically altered, to induce specific DES–solute interactions, and, thus, tune solubility. DESs were designed starting from the well-known cholinium chloride salt mixed with the partially amphiphilic 1,4-butanediol hydrogen bond donor (HBD), and then, the effect of increasing salt hydrophobicity (tetrabutylammonium bromide) and HBD hydrophobicity (p-cresol) was explored. Measurements were made between 2.5 and 25 wt. % H2O, as a reasonable range representing atmospherically absorbed water, and molecular dynamics simulations were used for structural analysis. The choline chloride:1,4-butanediol DES had the lowest indigo solubility, with only the hydrophobic character of the alcohol alkyl spacers. Solubility was highest for indigo in the tetrabutylammonium bromide:1,4-butanediol DES with 2.5 wt. % H2O due to interactions of indigo with the hydrophobic cation, but further addition of water caused this to reduce in line with the added water mole fraction, as water solvated the cation and reduced the extent of the hydrophobic region. The ChCl:p-cresol DES did not have the highest solubility at 2.5 wt. % H2O, but did at 25 wt. % H2O. Radial distribution functions, coordination numbers, and spatial distribution functions demonstrate that this is due to strong indigo–HBD interactions, which allow this system to resist the higher mole fraction of water molecules and retain its solubility. The DES is, therefore, a host to local-composition effects in solvation, where its hydrophobic moieties concentrate around the hydrophobic solute, illustrating the versatility of DES as solvents.

Published
2021

42. How accurate are EOM-CC4 vertical excitation energies?

Author

Denis Jacquemin, Pierre-François Loos, Devin A. Matthews, Filippo Lipparini, Groupe Méthodes et outils de la chimie quantique (LCPQ) (GMO), Laboratoire de Chimie et Physique Quantiques (LCPQ), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées, Chimie Et Interdisciplinarité : Synthèse, Analyse, Modélisation (CEISAM), Université de Nantes - Faculté des Sciences et des Techniques, Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS), European Project: 863481,PTEROSOR, Laboratoire de Chimie et Physique Quantiques Laboratoire (LCPQ), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), and Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)

Subjects
Chemical Physics (physics.chem-ph), Physics, Condensed Matter - Materials Science, Strongly Correlated Electrons (cond-mat.str-el), 010304 chemical physics, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, General Physics and Astronomy, Computational Physics (physics.comp-ph), Molecular systems, 010402 general chemistry, 01 natural sciences, Full configuration interaction, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Condensed Matter - Strongly Correlated Electrons, Physics - Chemical Physics, Excited state, 0103 physical sciences, Physical and Theoretical Chemistry, Atomic physics, Physics - Computational Physics, Excitation
Abstract

We report the first investigation of the performance of EOM-CC4 -- an approximate equation-of-motion coupled-cluster model which includes iterative quadruple excitations -- for vertical excitation energies in molecular systems. By considering a set of 28 excited states in 10 small molecules for which we have computed CCSDTQP and FCI reference energies, we show that, in the case of excited states with a dominant contribution from the single excitations, CC4 yields excitation energies with sub-kJ~mol$^{-1}$ accuracy (i.e., error below $0.01$ eV), in very close agreement with its more expensive CCSDTQ parent. Therefore, if one aims at high accuracy, CC4 stands as a highly competitive approximate method to model molecular excited states, with a significant improvement over both CC3 and CCSDT. Our results also evidence that, although the same qualitative conclusions hold, one cannot reach the same level of accuracy for transitions with a dominant contribution from the double excitations., 6 pages, 2 figures

Published
2021

43. Thermal evaporation of pyrene clusters

Author

Sébastien Zamith, Léo Dontot, Christine Joblin, Mathias Rapacioli, Mingchao Ji, Fernand Spiegelman, Jean-Marc L'Hermite, Agrégats (LCAR), Laboratoire Collisions Agrégats Réactivité (LCAR), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Modélisation, Agrégats, Dynamique (LCPQ) (MAD), Laboratoire de Chimie et Physique Quantiques (LCPQ), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Météo-France -Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo-France -Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), and Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)

Subjects
Materials science, 010304 chemical physics, Extrapolation, General Physics and Astronomy, Configuration interaction, 010402 general chemistry, 01 natural sciences, Molecular physics, Dissociation (chemistry), Article, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, chemistry.chemical_compound, Time of flight, Tight binding, Thermalisation, chemistry, 0103 physical sciences, Density of states, Pyrene, Physical and Theoretical Chemistry
Abstract

International audience; This work presents a study of the thermal evaporation and stability of pyrene (C 16 H 10) n clusters. Thermal evaporation rates of positively charged mass-selected clusters are measured for sizes in the range n=3-40 pyrene units. The experimental setup consists of a gas aggregation source, a thermalization chamber and a time of flight mass spectrometer. A microcanonical Phase Space Theory (PST) simulation is used to determine the dissociation energies of pyrene clusters by fitting the experimental breakdown curves. Calculations using the Density Functional based Tight Binding combined with Configuration Interaction (CI-DFTB) model and a hierarchical optimization scheme are also performed in the range n=2-7 to determine the harmonic frequencies and a theoretical estimation of the dissociation energies. The frequencies are used in the calculations of the density of states needed in the PST simulations, assuming an extrapolation scheme for clusters larger than 7 units. Using the PST model with a minimal set of adjustable parameters, we obtain good fits of the experimental breakdown curves over the full studied size range. The approximations inherent to the PST simulation and the influence of the used parameters are carefully estimated. The derived dissociation energies show significant variations over the studied size range. Compared to neutral clusters, significantly higher values of the dissociation energies are obtained for the smaller sizes and attributed to charge resonance in line with CI-DFTB calculations.

Published
2019

44. A matrix isolation ESR investigation of the MgCH radical

Author

Duncan A. Wild, Emmanuel Karakyriakos, Allan J. McKinley, Cara L. Dunford, Marcus Kettner, Thomas S. Hearne, Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Australian Research Council, Australian Government Department of Education Science and Training, Australian Government Research Training Program, Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, 010304 chemical physics, Radical, Matrix isolation, Analytical chemistry, General Physics and Astronomy, Electronic structure, 010402 general chemistry, 7. Clean energy, 01 natural sciences, Bond-dissociation energy, 0104 chemical sciences, law.invention, Bond length, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, law, 0103 physical sciences, Density functional theory, Physical and Theoretical Chemistry, Electron paramagnetic resonance, Hyperfine structure, ComputingMilieux_MISCELLANEOUS
Abstract

The MgCH radical and its magnesium-25, carbon-13, and deuterated isotopologs have been isolated in low temperature neon matrices and examined by the matrix isolation electron spin resonance technique for the first time. The radicals were formed through the reactions of laser ablated natural abundance magnesium metal and magnesium-25 enriched magnesium metal with carbon-13 and deuterated isotopologs of acetone. The MgCH radical was shown to have a X4Σ− ground electronic state, and the magnetic parameters determined for this state were g⊥ = 2.001 81(45), g∥ = 2.0018(10), D = 4970(5) MHz, A⊥(13C) = 115(6) MHz, A∥(13C) = 65(15) MHz, A⊥(H) = 34(6) MHz, A∥(H) = 5(10) MHz, A⊥(D) = 5(3) MHz, A⊥(25Mg) = 82(5) MHz, and A∥(25Mg) = 85(10). Comparisons are made between the electronic structure of this radical and the MgCH3 and MgN radicals. Theoretical hyperfine parameters were also evaluated for the MgCH radical, and a potential energy surface for the low-lying electronic states was constructed using complete active space multiconfigurational self-consistent field theory. The leading configuration (96.6%) for the X4Σ− ground electronic state was shown to be 1σ22σ23σ21π44σ25σ26σ27σ12π12π1 with an Mg–C bond length of 2.041 A for a fixed C–H bond length of 1.090 A. The Mg–C bond dissociation energy (De) was 48.26 kcal/mol. The optimized geometry from a density functional theory calculation using the B3LYP functional gave a Mg–C bond length of 2.061 A and a C–H bond length of 1.090 A.The MgCH radical and its magnesium-25, carbon-13, and deuterated isotopologs have been isolated in low temperature neon matrices and examined by the matrix isolation electron spin resonance technique for the first time. The radicals were formed through the reactions of laser ablated natural abundance magnesium metal and magnesium-25 enriched magnesium metal with carbon-13 and deuterated isotopologs of acetone. The MgCH radical was shown to have a X4Σ− ground electronic state, and the magnetic parameters determined for this state were g⊥ = 2.001 81(45), g∥ = 2.0018(10), D = 4970(5) MHz, A⊥(13C) = 115(6) MHz, A∥(13C) = 65(15) MHz, A⊥(H) = 34(6) MHz, A∥(H) = 5(10) MHz, A⊥(D) = 5(3) MHz, A⊥(25Mg) = 82(5) MHz, and A∥(25Mg) = 85(10). Comparisons are made between the electronic structure of this radical and the MgCH3 and MgN radicals. Theoretical hyperfine parameters were also evaluated for the MgCH radical, and a potential energy surface for the low-lying electronic states was constructed using complete active ...

Published
2019

45. Shear force measurement of the hydrodynamic wall position in molecular dynamics

Author

Cecilia Herrero, Yasutaka Yamaguchi, Takeshi Omori, Laurent Joly, Modélisation de la matière condensée et des interfaces (MMCI), Institut Lumière Matière [Villeurbanne] (ILM), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Osaka University [Osaka], and ANR-16-CE06-0004,NECtAR,Interfaces réactives pour la conversion d'énergie nanofluidique(2016)

Subjects
Laws of friction, Shear force, Microfluidics, General Physics and Astronomy, Slip (materials science), Molecular dynamics, 010402 general chemistry, 01 natural sciences, Physics::Fluid Dynamics, [SPI]Engineering Sciences [physics], Laminar flows, 0103 physical sciences, Shear stress, [CHIM]Chemical Sciences, Boundary value problem, Physical and Theoretical Chemistry, Physics, [PHYS]Physics [physics], 010304 chemical physics, Viscosity, Nanofluidics, Mechanics, Hagen–Poiseuille equation, 0104 chemical sciences, Liquid solid interfaces, Transport properties, Wetting
Abstract

Cecilia Herrero, Takeshi Omori, Yasutaka Yamaguchi, and Laurent Joly, "Shear force measurement of the hydrodynamic wall position in molecular dynamics", The Journal of Chemical Physics 151, 041103 (2019) https://doi.org/10.1063/1.5111966., Flows in nanofluidic systems are strongly affected by liquid-solid slip, which is quantified by the slip length and by the position where the slip boundary condition applies. Here, we show that the viscosity, slip length, and hydrodynamic wall position (HWP) can be accurately determined from a single molecular dynamics (MD) simulation of a Poiseuille flow, after identifying a relation between the HWP and the wall shear stress in that configuration. From this relation, we deduce that in gravity-driven flows, the HWP identifies with the Gibbs dividing plane of the liquid-vacuum density profile. Simulations of a generic Lennard-Jones liquid confined between parallel frozen walls show that the HWP for a pressure-driven flow is also close to the Gibbs dividing plane (measured at equilibrium), which therefore provides an inexpensive estimate of the HWP, going beyond the common practice of assuming a given position for the hydrodynamic wall. For instance, we show that the HWP depends on the wettability of the surface, an effect usually neglected in MD studies of liquid-solid slip. Overall, the method introduced in this article is simple, fast, and accurate and could be applied to a large variety of systems of interest for nanofluidic applications.

Published
2019

46. Filament flexibility enhances power transduction of F-actin bundles

Author

Alessia Perilli, Jean-Paul Ryckaert, Carlo Pierleoni, Dipartimento di Fisica [Roma La Sapienza], Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome], École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL), Department of Physical and Chemical Sciences [L'Aquila] (DSFC), Università degli Studi dell'Aquila (UNIVAQ), Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Faculté des Sciences [Bruxelles] (ULB), Université libre de Bruxelles (ULB), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome] (UNIROMA), École normale supérieure - Paris (ENS-PSL), Università degli Studi dell'Aquila = University of L'Aquila (UNIVAQ), and Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)

Subjects
Work (thermodynamics), Flexibility (anatomy), Optical Tweezers, [PHYS.PHYS.PHYS-BIO-PH]Physics [physics]/Physics [physics]/Biological Physics [physics.bio-ph], FOS: Physical sciences, General Physics and Astronomy, Physics - Biological Physics, Physics - Statistical Mechanics, Physics - Computational Physics, Molecular Dynamics Simulation, 010402 general chemistry, 01 natural sciences, Polymerization, Protein filament, Quantitative Biology::Subcellular Processes, [PHYS.PHYS.PHYS-COMP-PH]Physics [physics]/Physics [physics]/Computational Physics [physics.comp-ph], 0103 physical sciences, medicine, Physical and Theoretical Chemistry, [PHYS.COND.CM-SM]Physics [physics]/Condensed Matter [cond-mat]/Statistical Mechanics [cond-mat.stat-mech], Pliability, Condensed Matter - Statistical Mechanics, Persistence length, Physics, Stochastic Processes, Statistical Mechanics (cond-mat.stat-mech), 010304 chemical physics, Brownian ratchet, Mechanics, Function (mathematics), Computational Physics (physics.comp-ph), Actins, 0104 chemical sciences, medicine.anatomical_structure, Models, Chemical, Biological Physics (physics.bio-ph), Bundle, Relaxation (physics), Monte Carlo Method
Abstract

The dynamic behavior of bundles of actin filaments growing against a loaded obstacle is investigated through a generalized version of the standard multi filaments Brownian Ratchet model in which the (de)polymerizing filaments are treated not as rigid rods but as semi-flexible discrete wormlike chains with a realistic value of the persistence length. By stochastic dynamic simulations we study the relaxation of a bundle of $N_f$ filaments with staggered seed arrangement against a harmonic trap load in supercritical conditions. Thanks to the time scale separation between the wall motion and the filament size relaxation, mimiking realistic conditions, this set-up allows us to extract a full load-velocity curve from a single experiment over the trap force/size range explored. We observe a systematic evolution of steady non-equilibrium states over three regimes of bundle lengths $L$. A first threshold length $\Lambda$ marks the transition between the rigid dynamic regime ($L\Lambda$), where the velocity $V(F,L)$ is an increasing function of the bundle length $L$ at fixed load $F$, the enhancement being the result of an improved level of work sharing among the filaments induced by flexibility. A second critical length corresponds to the beginning of an unstable regime characterized by a high probability to develop escaping filaments which start growing laterally and thus do not participate anymore to the generation of the polymerization force. This phenomenon prevents the bundle from reaching at this critical length the limit behavior corresponding to Perfect Load Sharing., Comment: 26 pages, 11 figures

Published
2019

47. A mass-selective ion transfer line coupled with a uniform supersonic flow for studying ion-molecule reactions at low temperatures

Author

Alexander Lekkas, Nour Jamal-Eddine, Sophie Carles, Baptiste Joalland, Ludovic Biennier, Dimitris Papanastasiou, Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), National Center for Scientific Research 'Demokritos' (NCSR), Agence Nationale de la Recherche through the AnionCosChem Project [ANR-14-CE33-0013], Physique et Chimie du Milieu Interstellaire (PCMI) of CNRS/INSU, Programme National de Planetologie (PNP) of CNRS/INSU, INC/INP, CEA, CNES, ANR-14-CE33-0013,Anion Cos Chem,Explorer la Chimie et Spectroscopie des Anions Cosmiques(2014), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, 010304 chemical physics, Polyatomic ion, Transfer line, General Physics and Astronomy, 010402 general chemistry, 7. Clean energy, 01 natural sciences, 0104 chemical sciences, Ion, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Physics::Plasma Physics, Ionization, 0103 physical sciences, Molecule, Supersonic speed, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Physical and Theoretical Chemistry, Atomic physics, Quadrupole mass analyzer, Choked flow
Abstract

International audience; A new approach based on the uniform supersonic flow technique-a cold, thermalized de Laval expansion offering the advantage of performing experiments with condensable species-has been developed to study ion-molecule reactions at low temperatures. It employs a mass-selective radio frequency transfer line to capture and select ions from an adaptable ionization source and to inject the selected ions in the core of the supersonic expansion where rate coefficients and product branching can be measured from room temperature down to similar to 15 K. The transfer line incorporates segmented ion guides combining quadrupolar and octapolar field orders to maximize transmission through the differential apertures and the large pressure gradients encountered between the ionization source (similar to mbar), the quadrupole mass filter (similar to 10(-5) mbar), and the de Laval expansion (similar to mbar). All components were designed to enable the injection of cations and anions of virtually any m/z ratio up to 200 at near ground potential, allowing for a precise control over the momentum and thermalization of the ions in the flow. The kinetics and branching ratios of a selection of reactions have been examined to validate the approach. The technique will be instrumental in providing new insight on the reactivity of polyatomic ions and molecular cluster ions in astrophysical and planetary environments.

Published
2019

48. A kinetic-Monte Carlo perspective on active matter

Author

Werner Krauth, Juliane U. Klamser, Sebastian C. Kapfer, Laboratoire de Physique Statistique de l'ENS (LPS), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Physik komplexer Systeme (MPI-PKS), Max-Planck-Gesellschaft, Systèmes Classiques ou Quantiques en Interaction, Laboratoire de physique de l'ENS - ENS Paris (LPENS (UMR_8023)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Université Paris Diderot - Paris 7 (UPD7)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Université Paris Diderot - Paris 7 (UPD7)

Subjects
General Physics and Astronomy, Thermodynamics, FOS: Physical sciences, Gaussian processes, Disjoint sets, Condensed Matter - Soft Condensed Matter, 010402 general chemistry, 01 natural sciences, Classical statistical mechanics, Stochastic processes, Phase (matter), 0103 physical sciences, Thermodynamic states and processes, Kinetic Monte Carlo, Physical and Theoretical Chemistry, Condensed Matter - Statistical Mechanics, Phase diagram, Physics, Range (particle radiation), 010304 chemical physics, Statistical Mechanics (cond-mat.stat-mech), Isotropy, Probability theory, Monte Carlo methods, 0104 chemical sciences, Active matter, Phase transitions, Soft Condensed Matter (cond-mat.soft), [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Soft matter, Random walks, Hexatic phase
Abstract

We study non-equilibrium phases for interacting two-dimensional self-propelled particles with isotropic pair-wise interactions using a persistent kinetic Monte Carlo (MC) approach. We establish the quantitative phase diagram, including the motility-induced phase separation (MIPS) that is a commonly observed collective phenomena in active matter. In addition, we demonstrate for several different potential forms the presence of two-step melting, with an intermediate hexatic phase, in regions far from equilibrium. Increased activity can melt a two-dimensional solid and the melting lines remain disjoint from MIPS. We establish this phase diagram for a range of the inter-particle potential stiffnesses, and identify the MIPS phase even in the hard-disk limit. We establish that the full description of the phase behavior requires three independent control parameters., Comment: 11 pages, 10 figures

Published
2019

49. Effective diffusivity of microswimmers in a crowded environment

Author

Benoˆıt Coasne, Eric Bertin, Marvin Brun-Cosme-Bruny, Philippe Peyla, Salima Rafaï, Laboratoire Interdisciplinaire de Physique [Saint Martin d’Hères] (LIPhy), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire de Physique de l'ENS Lyon (Phys-ENS), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Lyon (ENS Lyon)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, and Laboratoire Interdisciplinaire de Physique [Saint Martin d’Hères] [2016-2019] (LIPhy [2016-2019])

Subjects
Physics, 010304 chemical physics, General Physics and Astronomy, FOS: Physical sciences, Observable, [CHIM.MATE]Chemical Sciences/Material chemistry, Condensed Matter - Soft Condensed Matter, 010402 general chemistry, Thermal diffusivity, Random walk, 01 natural sciences, Soft lithography, 0104 chemical sciences, Active matter, Lattice (order), 0103 physical sciences, Effective diffusion coefficient, Soft Condensed Matter (cond-mat.soft), Physical and Theoretical Chemistry, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], Biological system, [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft], Microfabrication
Abstract

International audience; The microalga Chlamydomonas Reinhardtii (CR) is used here as a model system to study the effect of complex environments on the swimming of microorganisms. Its motion can be modelled by a run and tumble mechanism so that it describes a persistent random walk from which we can extract an effective diffusion coefficient for the large-time dynamics. In our experiments, the complex medium consists in a series of pillars that are designed in a regular lattice using soft lithography microfabrication. The cells are then introduced in the lattice, and their trajectories within the pillars are tracked and analyzed. The effect of the complex medium on the swimming behaviour of microswimmers is analyzed through the measure of relevant statistical observables. In particular, the mean correlation time of direction and the effective diffusion coefficient are shown to decrease when increasing the density of pillars. This provides some bases of understanding for active matter in complex environments.

Published
2019

50. Low energy electron and positron impact differential cross sections for the ionization of water molecules in the coplanar and perpendicular kinematics

Author

D. Sebilleau, Christophe Champion, Prithvi Singh, Don H. Madison, Ghanshyam Purohit, Centre d'Etudes Lasers Intenses et Applications (CELIA), Université de Bordeaux (UB)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Missouri University of Science and Technology (Missouri S&T), University of Missouri System, Department of Science and Technology, DOSTMissouri University of Science and Technology, MST2017Department of Science and Technology, Ministry of Science and Technology, DST YSS/2015/001164American Physical Society, APS, Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Bordeaux (UB), Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Born approximation, Approximation results, General Physics and Astronomy, Electrons, Electron, 010402 general chemistry, 01 natural sciences, Distorted wave Born approximation, Ejected electrons, Positrons, Positron, Collision interaction, Ionization, Impact ionization, 0103 physical sciences, Electron energy levels, Perpendicular-plane, Physical and Theoretical Chemistry, [PHYS]Physics [physics], Physics, 010304 chemical physics, Plane (geometry), Scattering, Momentum transfer, Molecules, 0104 chemical sciences, Low energy electrons, Scattering angles, Distortion (waves), Ionization of liquids, Atomic physics, Differential cross section
Abstract

International audience; We report here triply differential cross sections (TDCSs) for 81 eV electron and positron-impact ionization of the combined (1b 1 + 3a 1 ) orbitals of the water molecule by using the second-order distorted wave Born approximation (DWBA2) for ejection electron and positron energies of 5 eV and 10 eV and different momentum transfer conditions. The electron-impact TDCS will be compared with the experimental data measured by Ren et al. [Phys. Rev. A 95, 022701 (2017)] and with the molecular 3-body distorted wave (M3DW) approximation results in the scattering plane as well as the perpendicular plane. The DWBA2 results are in better agreement with the experiment than the M3DW results for the scattering plane, and the M3DW results are somewhat better for the perpendicular plane. This observation is explained in terms of collision interactions. The electron and positron TDCSs are indistinguishable in the scattering plane. In the perpendicular plane, the positron results are similar in shape, but smaller in magnitude. However, the difference reduces with increasing projectile scattering angle and increasing ejected electron energy.

Published
2019

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