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1. Mass-Metallicity Trends in Transiting Exoplanets from Atmospheric Abundances of H$_2$O, Na, and K

Author

Welbanks, Luis, Madhusudhan, Nikku, Allard, Nicole F., Hubeny, Ivan, Spiegelman, Fernand, and Leininger, Thierry

Subjects
Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Solar and Stellar Astrophysics
Abstract

Atmospheric compositions can provide powerful diagnostics of formation and migration histories of planetary systems. We investigate constraints on atmospheric abundances of H$_2$O, Na, and K, in a sample of transiting exoplanets using latest transmission spectra and new H$_2$ broadened opacities of Na and K. Our sample of 19 exoplanets spans from cool mini-Neptunes to hot Jupiters, with equilibrium temperatures between $\sim$300 and 2700 K. Using homogeneous Bayesian retrievals we report atmospheric abundances of Na, K, and H$_2$O, and their detection significances, confirming 6 planets with strong Na detections, 6 with K, and 14 with H$_2$O. We find a mass-metallicity trend of increasing H$_2$O abundances with decreasing mass, spanning generally substellar values for gas giants and stellar/superstellar for Neptunes and mini-Neptunes. However, the overall trend in H$_2$O abundances, from mini-Neptunes to hot Jupiters, is significantly lower than the mass-metallicity relation for carbon in the solar system giant planets and similar predictions for exoplanets. On the other hand, the Na and K abundances for the gas giants are stellar or superstellar, consistent with each other, and generally consistent with the solar system metallicity trend. The H$_2$O abundances in hot gas giants are likely due to low oxygen abundances relative to other elements rather than low overall metallicities, and provide new constraints on their formation mechanisms. The differing trends in the abundances of species argue against the use of chemical equilibrium models with metallicity as one free parameter in atmospheric retrievals, as different elements can be differently enhanced., Comment: Accepted for publication in The Astrophysical Journal Letters

Published
2019
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2. A Wigner molecule at extremely low densities: a numerically exact study

Author

Azor, Miguel Escobar, Brooke, Léa, Evangelisti, Stefano, Leininger, Thierry, Loos, Pierre-François, Suaud, Nicolas, and Berger, J. A.

Subjects
Condensed Matter - Strongly Correlated Electrons
Abstract

In this work we investigate Wigner localization at very low densities by means of the exact diagonalization of the Hamiltonian. This yields numerically exact results. In particular, we study a quasi-one-dimensional system of two electrons that are confined to a ring by three-dimensional gaussians placed along the ring perimeter. To characterize the Wigner localization we study several appropriate observables, namely the two-body reduced density matrix, the localization tensor and the particle-hole entropy. We show that the localization tensor is the most promising quantity to study Wigner localization since it accurately captures the transition from the delocalized to the localized state and it can be applied to systems of all sizes., Comment: Resubmission to SciPost 8 pages, 3 figures

Published
2019
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4. A simple position operator for periodic systems

Author

Valença, Emilia Aragao, Moreno, Diego, Battaglia, Stefano, Bendazzoli, Gian Luigi, Evangelisti, Stefano, Leininger, Thierry, Suaud, Nicolas, and Berger, J. A.

Subjects
Condensed Matter - Other Condensed Matter
Abstract

We present a position operator that is compatible with periodic boundary conditions (PBC). It is a one-body operator that can be applied in calculations of correlated materials by simply replacing the traditional position vector by the new definition. We show that it satisfies important fundamental as well as practical constraints. To illustrate the usefulness of the PBC position operator we apply it to the localization tensor, a key quantity that is able to differentiate metallic from insulating states. In particular, we show that the localization tensor given in terms of the PBC position operator yields the correct expression in the thermodynamic limit. Moreover, we show that it correctly distinguishes between finite precursors of metals and insulators., Comment: 5 pages, 1 figure

Published
2018
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5. Local Orbitals in Quantum Chemistry

Author

Ben Amor, Nadia, Evangelisti, Stefano, Leininger, Thierry, Andrae, Dirk, Carpenter, Barry, Series Editor, Ceroni, Paola, Series Editor, Landfester, Katharina, Series Editor, Leszczynski, Jerzy, Series Editor, Luh, Tien-Yau, Series Editor, Perlt, Eva, Series Editor, Polfer, Nicolas C., Series Editor, and Salzer, Reiner, Series Editor

Published
2021
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8. Confinement of the Pentanitrogen Cation Inside Carbon Nanotubes

Author

Battaglia, Stefano, Evangelisti, Stefano, Leininger, Thierry, Faginas-Lago, Noelia, Hutchison, David, Series Editor, Kanade, Takeo, Series Editor, Kittler, Josef, Series Editor, Kleinberg, Jon M., Series Editor, Mattern, Friedemann, Series Editor, Mitchell, John C., Series Editor, Naor, Moni, Series Editor, Pandu Rangan, C., Series Editor, Steffen, Bernhard, Series Editor, Terzopoulos, Demetri, Series Editor, Tygar, Doug, Series Editor, Weikum, Gerhard, Series Editor, Gervasi, Osvaldo, editor, Murgante, Beniamino, editor, Misra, Sanjay, editor, Stankova, Elena, editor, Torre, Carmelo M., editor, Rocha, Ana Maria A.C., editor, Taniar, David, editor, Apduhan, Bernady O., editor, Tarantino, Eufemia, editor, and Ryu, Yeonseung, editor

Published
2018
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14. Modeling of the $\mathrm{N}_2^+$ ion in cold helium plasma II: transport properties of $\mathrm{N}_2^+$ in helium

Author

Paláček, Stanilas, Beseda, Martin, Kalus, René, Benhenni, Malika, Gadéa, Florent, Leininger, Thierry, Yousfi, Mohammed, IT4Innovations - National Supercomputing Center [Ostrava], Technical University of Ostrava [Ostrava] (VSB), Plasmas Réactifs Hors Equilibre (LAPLACE-PRHE), LAboratoire PLasma et Conversion d'Energie (LAPLACE), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT), Groupe Méthodes et outils de la chimie quantique (LCPQ) (GMO), Laboratoire de Chimie et Physique Quantiques Laboratoire (LCPQ), 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
Abstract

A detailed modeling of N$_2^+$ transport properties in helium gas has been performed by employing Monte Carlo calculations based on ab initio collision cross-sections reported by our group in a preceding paper (S Paláček et al 2022 Plasma Sources Sci. Technol. 31 105004). A broad range of the reduced electric field ($E/N$) is considered to provide data directly usable in macroscopic modeling of processes in cold helium plasmas. The N$_2^+$ mobility in helium gas at room temperature (T = 300 K), the characteristic energies of its longitudinal and transversal diffusion, and the rate constant of the N$_2^+$ dissociation induced by collisions with helium atoms have been calculated. The effect of the N$_2^+$ initial rotational-vibrational excitation is investigated as well as the effect of the rotational alignment of the N$_2^+$ molecule. A direct comparison with N$_2^+$/He mobility experimental data is performed as well as indirect tests of theoretical estimates of the characteristic diffusion energies by comparing the latter with pseudo-experimental data obtained from mobility experiments via an inverse-method approach

Published
2023
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20. Ab-Initio Multi-reference Study of a Bistable Spiro Molecule

Author

Helal, Wissam, Bories, Benoît, Evangelisti, Stefano, Leininger, Thierry, Maynau, Daniel, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Dough, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Gavrilova, Marina, editor, Gervasi, Osvaldo, editor, Kumar, Vipin, editor, Tan, C. J. Kenneth, editor, Taniar, David, editor, Laganá, Antonio, editor, Mun, Youngsong, editor, and Choo, Hyunseung, editor

Published
2006
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21. Ab initio approaches for N 2 + and N 2 + / He ions towards modeling of the N 2 + ion in cold helium plasma

Author

Beseda, Martin, Paláček, S., Gadéa, Florent, Leininger, Thierry, Kalus, René, Benhenni, Malika, Yousfi, Mohammed, IT4Innovations - National Supercomputing Center [Ostrava], Technical University of Ostrava [Ostrava] (VSB), Faculty of Electrical Engineering and Computer Science, 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), Plasmas Réactifs Hors Equilibre (LAPLACE-PRHE), LAboratoire PLasma et Conversion d'Energie (LAPLACE), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)

Subjects
[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry
Abstract

International audience

Published
2022
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25. Multilayer Graphtriyne Membranes for Separation and Storage of CO2: Molecular Dynamics Simulations of Post-Combustion Model Mixtures

Author

Università degli Studi di Perugia, Ministerio de Economía y Competitividad (España), Apriliyanto, Y. B., Faginas-Lago, N., Evangelisti, S., Bartolomei, Massimiliano, Leininger, Thierry, Pirani, Fernando, Pacifici, Leonardo, Lombardi, Andrea, Università degli Studi di Perugia, Ministerio de Economía y Competitividad (España), Apriliyanto, Y. B., Faginas-Lago, N., Evangelisti, S., Bartolomei, Massimiliano, Leininger, Thierry, Pirani, Fernando, Pacifici, Leonardo, and Lombardi, Andrea

Abstract

The ability to remove carbon dioxide from gaseous mixtures is a necessary step toward the reduction of greenhouse gas emissions. As a contribution to this field of research, we performed a molecular dynamics study assessing the separation and adsorption properties of multi-layered graphtriyne membranes on gaseous mixtures of CO, N, and HO. These mixtures closely resemble post-combustion gaseous products and are, therefore, suitable prototypes with which to model possible technological applications in the field of CO removal methodologies. The molecular dynamics simulations rely on a fairly accurate description of involved force fields, providing reliable predictions of selectivity and adsorption coefficients. The characterization of the interplay between molecules and membrane structure also permitted us to elucidate the adsorption and crossing processes at an atomistic level of detail. The work is intended as a continuation and a strong enhancement of the modeling research and characterization of such materials as molecular sieves for CO storage and removal.

Published
2022

37. Multilayer Graphtriyne Membranes for Separation and Storage of CO 2 : Molecular Dynamics Simulations of Post-Combustion Model Mixtures.

Author

Apriliyanto, Yusuf Bramastya, Faginas-Lago, Noelia, Evangelisti, Stefano, Bartolomei, Massimiliano, Leininger, Thierry, Pirani, Fernando, Pacifici, Leonardo, and Lombardi, Andrea

Subjects
MOLECULAR dynamics, MEMBRANE separation, COMBUSTION kinetics, GREENHOUSE gas mitigation, CARBON dioxide, MIXTURES, GEOLOGICAL carbon sequestration
Abstract

The ability to remove carbon dioxide from gaseous mixtures is a necessary step toward the reduction of greenhouse gas emissions. As a contribution to this field of research, we performed a molecular dynamics study assessing the separation and adsorption properties of multi-layered graphtriyne membranes on gaseous mixtures of CO2, N2, and H2O. These mixtures closely resemble post-combustion gaseous products and are, therefore, suitable prototypes with which to model possible technological applications in the field of CO2 removal methodologies. The molecular dynamics simulations rely on a fairly accurate description of involved force fields, providing reliable predictions of selectivity and adsorption coefficients. The characterization of the interplay between molecules and membrane structure also permitted us to elucidate the adsorption and crossing processes at an atomistic level of detail. The work is intended as a continuation and a strong enhancement of the modeling research and characterization of such materials as molecular sieves for CO2 storage and removal. [ABSTRACT FROM AUTHOR]

Published
2022
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38. Toward a Generalized Hückel Rule : The Electronic Structure of Carbon Nanocones

Author

Apriliyanto, Yusuf Bramastya, Battaglia, Stefano, Evangelisti, Stefano, Faginas-Lago, Noelia, Leininger, Thierry, Lombardi, Andrea, Apriliyanto, Yusuf Bramastya, Battaglia, Stefano, Evangelisti, Stefano, Faginas-Lago, Noelia, Leininger, Thierry, and Lombardi, Andrea

Abstract

In this work, we investigate a particular class of carbon nanocones, which we name graphannulenes, and present a generalized Hückel rule (GHR) that predicts the character of their ground state based on simply the three topological indices that uniquely define them. Importantly, this rule applies to both flat and curved systems, encompassing a wide variety of known structures that do not satisfy the “classic” 4n + 2 rule such as coronene, corannulene, and Kekulene. We test this rule at the Hückel level of theory for a large number of systems, including structures that are convex and flat, with a saddle-like geometry, and at the CASSCF level of theory for a selected representative subset. All the performed calculations support the GHR that we propose in this work., Title in Web of Science: Toward a Generalized Huckel Rule: The Electronic Structure of Carbon Nanocones

Published
2021
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43. Reduction behavior of the early actinyl ions in aqueous solution

Author

Vallet, Valerie, Maron, Laurent, Schimmelpfennig, Bernd, Leininger, Thierry, Teichteil, Christian, Gropen, Odd, Grenthe, Ingmar, and Wahlgren, Ulf

Subjects
Actinide elements -- Research, Ions -- Research, Chemicals, plastics and rubber industries
Abstract

A systematic investigation of the reduction properties of the actinyl ions XO(sub 2)(super 2+) is presented. It has been possible to clearly show the stability of neptunium(V).

Published
1999

44. Local orbitals for quasi-degenerate systems

Author

Evangelisti, Stefano, Guihéry, Nathalie, Leininger, Thierry, Malrieu, Jean-Paul, Maynau, Daniel, Pitarch Ruiz, José-Vicente, Suaud, Nicolas, Angeli, Celestino, Cimiraglia, Renzo, and Calzado, Carmen J.

Published
2004
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45. Electronic structure and bonding energetics of a complex undergoing intramolecular disproportionation: ab initio two-configuration SCF and CI investigation on O3ReReCl2(H2PCH2PH2)2

Author

Costas, Miquel, Leininger, Thierry, Gwang-Hi Jeung, and Benard, Marc

Subjects
Electronic structure -- Research, Atomic orbitals -- Research, Chemistry
Abstract

Ab initio calculations on O3ReReCl2(H2PCH2PH2)2 were performed to determine whether the ReCl2(dmpm)2 fragment is a sigma donor toward the trioxorhenium or if a different bonding mechanism is in effect. Results revealed that the pentagonal pyramid structure adopted by the ReCl2(dmpm) moiety leads to a charge transfer toward a 5d(sub z super 2)/6s hybrid orbital of the trioxorhenium orbital. As a consequence, the polarized metal-metal bond may be considered as a sigma donation from the trioxorhenium fragment to the ReCl2(dmpm)2 unit.

Published
1992

46. The spin-partitioned total position-spread tensor: An application to Heisenberg spin chains.

Author

Fertitta, Edoardo, El Khatib, Muammar, Bendazzoli, Gian Luigi, Paulus, Beate, Evangelisti, Stefano, and Leininger, Thierry

Subjects
HEISENBERG model, BOUNDARY value problems, FERROMAGNETISM, GROUND state (Quantum mechanics), MAGNETIC coupling, THERMODYNAMICS
Abstract

The spin partition of the Total Position-Spread (TPS) tensor has been performed for one-dimensional Heisenberg chains with open boundary conditions. Both the cases of a ferromagnetic (high-spin) and an anti-ferromagnetic (low-spin) ground-state have been considered. In the case of a low-spin ground-state, the use of alternating magnetic couplings allowed to investigate the effect of spinpairing. The behavior of the spin-partitioned TPS (SP-TPS) tensor as a function of the number of sites turned to be closely related to the presence of an energy gap between the ground-state and the first excited-state at the thermodynamic limit. Indeed, a gapped energy spectrum is associated to a linear growth of the SP-TPS tensor with the number of sites. On the other hand, in gapless situations, the spread presents a faster-than-linear growth, resulting in the divergence of its per-site value. Finally, for the case of a high-spin wave function, an analytical expression of the dependence of the SP-TPS on the number of sites n and the total spin-projection Sz has been derived. [ABSTRACT FROM AUTHOR]

Published
2015
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47. The total position-spread tensor: Spin partition.

Author

El Khatib, Muammar, Brea, Oriana, Fertitta, Edoardo, Bendazzoli, Gian Luigi, Evangelisti, Stefano, and Leininger, Thierry

Subjects
QUANTUM entanglement, HYDROGEN, METAL-insulator transitions, PHASE transitions, MAGNETIC fields, ELECTRONIC structure, PARTITION coefficient (Chemistry), NUCLEAR spin
Abstract

The Total Position Spread (TPS) tensor, defined as the second moment cumulant of the position operator, is a key quantity to describe the mobility of electrons in a molecule or an extended system. In the present investigation, the partition of the TPS tensor according to spin variables is derived and discussed. It is shown that, while the spin-summed TPS gives information on charge mobility, the spin-partitioned TPS tensor becomes a powerful tool that provides information about spin fluctuations. The case of the hydrogen molecule is treated, both analytically, by using a 1s Slater-type orbital, and numerically, at Full Configuration Interaction (FCI) level with a V6Z basis set. It is found that, for very large inter-nuclear distances, the partitioned tensor growths quadratically with the distance in some of the low-lying electronic states. This fact is related to the presence of entanglement in the wave function. Non-dimerized open chains described by a model Hubbard Hamiltonian and linear hydrogen chains Hn (n ≥ 2), composed of equally spaced atoms, are also studied at FCI level. The hydrogen systems show the presence of marked maxima for the spin-summed TPS (corresponding to a high charge mobility) when the inter-nuclear distance is about 2 bohrs. This fact can be associated to the presence of a Mott transition occurring in this region. The spin-partitioned TPS tensor, on the other hand, has a quadratical growth at long distances, a fact that corresponds to the high spin mobility in a magnetic system. [ABSTRACT FROM AUTHOR]

Published
2015
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49. Spherical aromaticity and electron delocalization in C8 and B4N4 cubic systems

Author

Chaglayan, Buse, Huran, Ahmad, Ben Amor, Nadia, Brumas, Véronique, Evangelisti, Stefano, Leininger, Thierry, Instituto de Ciencia Molecular (ICMol), Universitat de València (UV), 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), 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 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), Martin-Luther-Universität Halle-Wittenberg, Martin-Luther-Universität Halle Wittenberg (MLU), Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3)

Subjects
[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2019
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50. Correlated and Non-Correlated Wave Functions for Organometallics

Author

Rohmer, Marie-Madeleine, primary, Costas, Miquel, additional, Ernenwein, René, additional, Kempf, Jean-Yves, additional, Ulmschneider, Michel, additional, de Vaal, Pieter, additional, Leininger, Thierry, additional, Jeung, Gwang-Hi, additional, Wiest, Roland, additional, and Bénard, Marc, additional

Published
1994
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