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Moisture is an important factor affecting the insulation properties of transformers. Due to the limitations of macroscopic experimental methods, the diffusion of water at oil–paper interface cannot...

The following collection of 25 papers has been submitted in honour of Professor Tim Softley, FRS to mark his 60th birthday. These papers tell us much about the man honoured in this special issue. T...

In this paper, we discuss the impact of using a frequency-dependent embedding potential in quantum chemical embedding calculations of response properties. We show that the introduction of a frequency-dependent embedding potential leads to further model complications upon solving the central equations defining specific molecular properties. On the other hand, we also show from a numerical point of view that the consequences of using such a frequency-dependent embedding potential is almost negligible. Thus, for the kind of systems and processes studied in this paper the general recommendation is to use frequency-independent embedding potentials since this leads to less complicated model issues. However, larger effects are expected if the absorption bands of the environment are closer to that of the region treated using quantum mechanics.

In this paper, we report vibrational energy levels of some tetraphenylporphyrins and its cation radicals, i.e. Cu[TPP], Cu[TPP]+, Ni(TPP), Ni(TPP)+, ClFe(TPP) and ClFe(TPP)+ using U(2) algebraic model Hamiltonian. In our study, we have used five fitting parameters which provide better comparisons between the experimental and theoretical calculations throughout the study. RMS deviation has been improved in this paper due to the inclusion of intermode couplings in algebraic model.Structure of metalloporphyrinsIn our work, we study the spectroscopic features of some biomolecules using Lie algebraic methods. This will be sought to be accomplished by studying the different vibrational energy levels as function of vibrational quantum numbers for certain biomolecules. Possibilities of local-to-normal transition in viable cases will be taken into consideration. In addition, new vibrational parameters for certain biomolecules will be sought to be identified for cases where Lie algebraic approach has not be...

Organic light-emitting diodes (OLEDs) have been widely used in various fields such as sensors. In this article, we designed six novel heterocyclic Ir(III) complexes: (CFM)2Ir(acac) (named 1 in this paper), (TTIQ)2Ir(acac) (named 2), (CFM)2Ir(tmd) (named 3), (TTIQ)2Ir(tmd) (named 4), (CFM)2Ir(pic) (named 5) and (TTIQ)2Ir(pic) (named 6). The six iridium (III) complexes were calculated using Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT). We studied the bands of the lowest-lying absorptions and lowest energy emissions of complexes 1–6. In addition, we also explored their spectral properties, frontier Molecular Orbital theory(FMO) and spin-orbital coupling value(SOC). Where acac is represented as pentane-2, 4-dione; tmd as 2,2,6,6-tetramethylheptane-3,5-dione; pic as pyridine-2-carboxylate; TTIQ as 1-{thieno[3,2-b]thiophen-2-yl}isoquinoline; CFM as 2-(4-fluorobrobenyl)-4-methylpyridine. A series of heteroleptic cyclometalated Ir (III) complexes, which are used for OLED application, were investigated by DFT and TD-DFT method. The frontier molecular orbital character and charge transfer character shown that they have the advantages of low efficiency roll-off properties, which is a ‘stumbling block’ in the process of OLED solid-lighting’s development. Namely, means the materials will play an important role in the journey development of OLED.

Thermally activated delayed fluorescence (TADF) molecules with dual emission have attracted extensive attention recently. However, the dual emission mechanism is complex and difficult to be studied especially in solid state. In this paper, asymmetrical diphenylketone derivatives CPzP and CPzPO are investigated in both benzene and in aggregation state with polarisable continuum model (PCM) and combined quantum mechanics and molecular mechanics (QM/MM) method respectively. It is found that there are both quasi-axial (ax) and quasi-equatorial (eq) conformations for CPzP and CPzPO in benzene. The ax conformation is responsible for the high energy band emission, while the low energy band emission is contributed by eq conformations. The dimers with intermolecular hydrogen bond have similar emission wavelengths with monomers. The small energy gap between the first singlet excited state and the first triplet excited state as well as large reverse intersystem crossing rate in eq conformations confirms the generation of TADF in eq conformation, which agree with experimental results that the low energy band emission is TADF. Our calculation results revealed the dual emission mechanism of two TADF molecules, which would favor the understanding of light emitting properties and the design of new type dual emission TADF emitters.

Photochemical reactions often involve states that are closely coupled due to near degeneracies, for example by proximity to conical intersections. Therefore, a multistate method is used to accurately describe these states; for example, ordinary perturbation theory is replaced by quasidegenerate perturbation theory. Multiconfiguration pair-density functional theory (MC-PDFT) provides an efficient way to approximate the full dynamical correlation energy of strongly correlated systems, and we recently proposed compressed multistate pair-density functional theory (CMS-PDFT) to treat closely coupled states. In the present paper, we report the implementation of analytic gradients for CMS-PDFT in both OpenMolcas and PySCF, and we illustrate the use of these gradients by applying the method to the excited states of formaldehyde and phenol.

Quasi-bound resonances of H$_2$ are produced via two-photon photolysis of H$_2$S molecules as reactive intermediates or transition states, and detected before decay of the parent molecule into three separate atoms. As was previously reported [K.F. Lai et al., Phys. Rev. Lett. 127, 183001 (2021)] four centrifugally bound quantum resonances with lifetimes of multiple $\mu$s, lying energetically above the dissociation limit of the electronic ground state X$^1\Sigma_g^+$ of H$_2$, were observed as X($v,J$) = (7,21)$^*$, (8,19)$^*$, (9,17)$^*$, and (10,15)$^*$, while also the short-lived ($\sim 1.5$ ns) quasi-bound resonance X(11,13)$^*$ was probed. The present paper gives a detailed account on the identification of the quasi-bound or shape resonances, based on laser detection via F-X two-photon transitions, and their strongly enhanced Franck-Condon factors due to the shifting of the wave function density to large internuclear separation. In addition, the assignment of the rotational quantum number is verified by subsequent multi-step laser excitation into autoionization continuum resonances. Existing frameworks of full-fledged ab initio computations for the bound region in H$_2$, including Born-Oppenheimer, adiabatic, non-adiabatic, relativistic and quantum-electrodynamic contributions, are extended into the energetic range above the dissociation energy. These comprehensive calculations are compared to the accurate measurements of energies of quasi-bound resonances, finding excellent agreement. Etc., Comment: Accepted Molecular Physics

This paper is the second of two back-to-back works, whose goal was to generate a more accurate linelist for the 5.8 µm absorption band of HNO3. Here, we report improved line positions and intensiti...

In this paper, Scarf II potential is used to construct the improved Scarf II potential energy function (ISPEF) for applications to diatomic molecules. Conditions to be satisfied by a diatomic molec...

This paper presents a unified model of gas phase acetone photophysics and photochemistry that is based on experimental data, which are reviewed and discussed in detail, and a detailed microcanonica...

In this paper, we present a molecular dynamics study of the glass transition for a soft-core primitive model for ionic liquids, in which cations are fully flexible chains of tangent soft spherical ...

Oxidative decomposition of solid lithium peroxide is an important part of the charging process in a Li-O2 battery. In this paper, we investigate oxidative decomposition mechanisms of lithium peroxide clusters as molecular models for solid lithium peroxide using density functional methods to understand charging processes in advanced energy storage systems. Most calculations are done using a (Li2O2)4 cluster with similar results obtained from a larger (Li2O2)16 cluster. Reaction pathways of the clusters involving different sequences of oxidation, oxygen evolution, lithium cation removal, and spin excitation are investigated. The computations suggest that certain oxidative decomposition routes may not have dependence on the oxygen evolution or Li-ion removal kinetics due to the exothermicity of oxygen removal and Li+ removal (by solvent) upon oxidation. The computed charge potentials evaluated using a tetramer model indicates that it is possible to have low overcharge potential provided there exists a good electronic conductivity to facilitate the oxidative decomposition. Finally, oxidation potentials of a series of LixOy clusters are investigated to assess their dependence on stoichiometry and how the local site from which the electrons are being removed affects the charge potentials.

The aim of this paper is a better comprehension of the encapsulation and interaction an anticancer drug Altretamine into BN nano ring [BNNR(9,9-5)] and AlN nano ring [AlNNR(9,9-5)]. The electronic ...

In this paper, the formalism describing the spontaneous emission rate of an excited molecule (or atom) with definite transition electric dipole moment, in vicinity of a perfect conductive wall is d...

Building on our previous work on NO + Ar, this paper presents a complete set of orientation measurements and quantum mechanical calculations for the NO + Kr collision system, including both spin-orbit conserving and changing collisions, and both side-on (x-axis) and end-on (z-axis) orientations. While many of the trends observed in the oriented differential and integral scattering distributions, as well as in the spin-orbit branching fractions, are similar to the ones seen previously for NO + Ar, a direct comparison with the Ar data reveals subtle differences in the scattering dynamics, which we rationalise with the more extended attractive regions on the NO + Kr potential energy surfaces. High-impact parameter collisions that lead to low scattering angles in the spin-orbit conserving manifold are particularly sensitive to the topology in the attractive parts of the potential, whereas more impulsive, low-impact parameter trajectories, which sample the repulsive parts of the potential, produce very similar features in the oriented differential cross sections for the Ar and Kr systems, especially for spin-orbit changing collisions.

In this paper, we present a Monte Carlo simulation study on the charge distribution and structure of a shape- and size-asymmetric electric double layer around a spherical colloid. Specifically, the...

Spontaneous emission (SE) is usually studied within the framework of quantum dissipation theory. In this paper we pursue a different view of SE. Namely, we take advantage of Nonhermitian Qu...

Novel ways to reduce the computational effort for atomic structure prediction while retaining high accuracy are of wide interest. This paper describes an implementation of the method of averaging over the wave vector k for the description of the lithium condensation. We show that the direct transition from the gas phase to the crystalline one is complicated. The formation of the crystal structure occurs through the condensation of individual small clusters.

International audience; The confined dynamics of water molecules inside a pore involves an intermittence between adsorption steps near the interface and surface diffusion and excursions in the pore network. Depending on the strength of the interaction in the layer(s) close to the surface and the dynamical confinement of the distal bulk liquid, exchange dynamics can vary significantly. The average time spent in the surface proximal region (also called the adsorption layer) between a first entry and a consecutive exit allows estimating the level of ‘nanowettablity’ of water. As shown in several seminal works, NMRD is an efficient experimental method to follow such intermittent dynamics close to an interface. In this paper, the intermittent dynamics of a confined fluid inside nanoporous materials is discussed. Special attention is devoted to the interplay between bulk diffusion, adsorption and surface diffusion on curved pore interfaces. Considering the nano or meso length scale confinement of the pore network, an analytical model for calculating the inter-dipolar spin–lattice relaxation dispersion curves is proposed. In the low-frequency regime (50 KHz–100 MHz), this model is successfully compared with numerical simulations performed using a 3D-off lattice reconstruction of Vycor glass. Comparison with experimental data available in the literature is finally discussed.

Seeking environmentally friendly gas-insulated medium has become a research hotspot in recent years. At present, C3F7CN (Heptafluoro-iso-butyronitrile) is considered to be a potential SF6 environment-friendly alternative gas and some achievements have been made in the study of its insulation and decomposition characteristics, but there are few reports on the compatibility between its characteristic decomposition products and materials. The investigation of compatibility between gas-insulated medium and material is an important part of evaluating its comprehensive performance. In this paper, we investigated the interaction between C2F5CN, CF3CN, COF2 and CF4 with the aluminium widely used in electrical equipment. It was found that the interaction between C2F5CN, CF3CN and Al (1 1 1) surface is strong. There are obvious charge transfer and electron orbital overlap between the C atom, N atom in CN group and Al (1 1 1). The interaction between COF2, CF4 and Al (1 1 1) surface is weak and van der Waal’...

Hierarchical self-assembly underpins much of the diversity of form and function seen in soft systems, yet the pathways by which they achieve their final form are not always straightforward – intermediate steps, kinetic effects and finite sizes of aggregates all influence the self-assembly pathways of these systems. In this paper, we use molecular dynamics simulations of binary mixtures of spheres and ellipsoidal discs to investigate the self-assembly of anisotropic aggregates with internal structures. Through this, the full aggregation pathways of spontaneously chiral, multi-bilayer and multi-layer assemblies have been tracked and characterised via a semi-qualitative analysis. This includes the unambiguous identification of first-, second- and third-generation hierarchical assemblies within a single simulation. Given the significant challenge of tracking full aggregation pathways in experimental systems, our findings strongly support the notion that molecular simulation has much to contribute to improving our understanding of hierarchical self-assembling systems.

The paper by Nold et al. [Phys. Fluids 26 (7), 072001 (2014)] examined density profiles and the micro-scale structure of an equilibrium three-phase (liquid–vapour–solid) contact line in the immediate vicinity of the wall using elements from the statistical mechanics of classical fluids, namely density-functional theory. The present research note, building on the above work, further contributes to our understanding of the nanoscale structure of a contact line by quantifying the strong dependence of the liquid–vapour density profile on the normal distance to the interface, when compared to the dependence on the vertical distance to the substrate. A recent study by Benet et al. [J. Phys. Chem. C 118 (38), 22079 (2014)] has shown that this could explain the emergence of a film-height-dependent surface tension close to the wall, with implications for the Frumkin–Derjaguin theory.

The time reversal invariance of classical dynamics is reconsidered in this paper with specific focus on its consequences for time correlation functions and associated properties such as transport coefficients. We show that, under fairly common assumptions on the interparticle potential, an isolated Hamiltonian system obeys more than one time reversal symmetry and that this entails non trivial consequences. Under an isotropic and homogeneous potential, in particular, eight valid time reversal operations exist. The presence of external fields that reduce the symmetry of space decreases this number, but does not necessarily impair all time reversal symmetries. Thus, analytic predictions of symmetry properties of time correlation functions and, in some cases, even of their null value are still possible. The noteworthy case of a constant external magnetic field, usually assumed to destroy time reversal symmetry, is considered in some detail. We show that, in this case too, some of the new time reversal operations hold, and that this makes it possible to derive relevant properties of correlation functions without the uninteresting inversion of the direction of the magnetic field commonly enforced in the literature. [GRAPHICS] .

The so-called Gibbs paradox is a paradigmatic narrative illustrating the necessity to account for the N! ways of permuting N identical particles when summing over microstates. Yet, there exist some mixing scenarios for which the expected thermodynamic outcome depends on the viewpoint one chooses to justify this combinatorial term. After a brief summary on Gibbs' paradox and what is the standard rationale used to justify its resolution, we will allow ourself to question from a historical standpoint whether the Gibbs paradox has actually anything to do with Gibbs' work. In so doing, we also aim at shedding a new light with regards to some of the theoretical claims surrounding its resolution. We will then turn to the statistical thermodynamics of discrete and continuous mixtures and introduce the notion of composition entropy to characterise these systems. This will enable us to address, in a certain sense, a "curiosity" pointed out by Gibbs in a paper published in 1876. Finally, we will �nish by proposing a connexion between the results we propose and a recent extension of the Landauer bound regarding the minimum amount of heat to be dissipated to reset one bit of memory.

This paper presents a comprehensive account on the recently developed dissipaton–equation–of–motion (DEOM) theory. This is a statistical quasi-particle theory for quantum dissipative dynamics. It a...

The hierarchy of stochastic Schrodinger equation, previously developed under the unpolarised initial bath states, is extended in this paper for open quantum dynamics under polarised initial bath conditions. The method is proved to be a powerful tool in investigating quantum dynamics exposed to an ultraslow Ohmic bath, as in this case the hierarchical truncation level and the random sampling number can be kept at a relatively small extent. By systematically increasing the system–bath coupling strength, the symmetric Ohmic spin-boson dynamics is investigated at finite temperature, with a very small cut-off frequency. It is confirmed that the slow bath makes the system dynamics extremely sensitive to the initial bath conditions. The localisation tendency is stronger in the polarised initial bath conditions. Besides, the oscillatory coherent dynamics persists even when the system–bath coupling is very strong, in correspondence with what is found recently in the deep sub-Ohmic bath, where also the low-...

In this paper, we present a chain-of-sphere implementation of the external exchange term, the computational bottleneck of coupled-cluster calculations at the singles and doubles level. This impleme...

The paper presents the results of ab initio modelling of the interaction of hydrogen atoms with ferrite/cementite interfaces in steels and thermodynamic assessment of the ability of interfaces to t...

Substantial progress of the time-dependent density matrix renormalisation group (t-DMRG) method in the recent 15 years is reviewed in this paper. By integrating the time evolution with the sweep pr...

In this paper, the vacancy formation at the interface between different grains (Ag3Sn and βSn) induced by electromigration was investigated from the perspective of atom diffusion. To explain the mi...

A combination of Hamilton–Jacobi equation and fast marching algorithm can be used to study reaction dynamics by converting the potential energy surface to a reaction action surface. The reaction action surface has been found to be an important tool in theoretical chemistry, allowing us to provide a different force-based perspective of chemical reactions. Several properties such as reaction force, reaction force surface, reaction path force and reaction path force constant have been defined and calculated by using the reaction action surface. This paper investigates these newly defined properties in order to understand the role they play in chemical reaction with reference to a model 4-well potential energy surface.

In this paper, the spin-Hamiltonian parameters (g factors gx, gy, gz and hyperfine structure constants A Ax, Ay, Az) and the absorption spectrum of K2CrO4 : Mn6 + crystal are theoretically explained by using the high-order perturbation theory, the double-spin-orbit-coupling model theory and the double-mechanism theory (the crystal field mechanism and the charge-transfer (CT) mechanism). The calculation results show that the contribution of the CT mechanism cannot be neglected for Mn6 + ions in orthorhombic clusters with the ground state .

In this paper, density functional theory method was employed to study the electronic absorption spectrum and electronic static second hyperpolarisability of X-shaped pyrazine derivatives with two-dimensional charge-transfer structures. Computational results show that the push–pull electron abilities of the substituent groups and the length of the conjugated chains affect the electronic spectrum and static second hyperpolarisability of the pyrazine derivatives. As the push–pull electron abilities of the substituent groups or the length of the conjugated chains increases, the frontier molecular orbital energy gap decreases, resulting in increased second hyperpolarisability and redshift of the electronic absorption bands. The electronic absorption spectra of the pyrazine derivatives maintain good transparency in the blue light band. The electronic static second hyperpolarisability exhibits a linear relationship to the frontier molecular orbital energy gap. Particularly, increasing/decreasing the push...

WOS: 000416731800006, In the present paper, new and useful theoreticalmethods for the estimation of cohesive energy density (Ced) and isothermal compressibility (k(T)) of alkali metal halides are described. The mentioned theoretical methods include the use of Kaya molecular hardness equation published by us in recent years. Cohesive energy density and isothermal compressibility of alkali metal halides were calculated in the framework of mentioned theoretical methods and the results obtained were compared with both experimental data and the results of previous theoretical methods proposed to calculate the aforementioned quantities, namely cohesive energy density and isothermal compressibility. It is important to note that the results obtained in the study are in good agreement with the available experimental data and with the results of previous theoretical methods. Additionally, we also investigated the correlation with lattice energy of cohesive energy density and isothermal compressibility for alkali halides. [GRAPHICS] .

In this paper, we investigate the electronic and magnetic properties of Cu-doped nickel clusters by means of density functional theory. The stabilities of these clusters have also been studied in terms of the binding energies, second-order difference of energies, fragmentation energies and HOMO–LUMO energy gaps. The obtained results reveal that the N4Cu, N5Cu and Ni7Cu clusters are found to be more stable that than all other clusters. Higher HOMO–LUMO gap was observed for Ni5Cu cluster (2.265 eV), indicating its higher chemical stability. A half-metallic behaviour has also been observed for the NinCu clusters, which suggests that these clusters can be employed as nanocatalysts for several catalytic processes, particularly for hydrogenation and dehydrogenation reactions. The magnetism calculations show that the magnetic moment is mostly located on the Ni atoms, and the contribution of the Cu atom to the total magnetic moment in the NinCu clusters is very small. Furthermore, partial density of state...

Genuine quantumness present in quantum systems is the resource for implementing quantum information and computation protocols which can outperform the classical counterparts. These quantumness measures encompass non-local ones known as quantum entanglement (QE) and quantum information theoretic ones, e.g. quantum discord (QD). In this paper, some well-known measures of QE and QD have been studied in two wheel-like frustrated molecular magnetic systems, with special emphasis on the survival of the measures in the thermal states. A molecular magnetic system similar to the first one (with half-integer spins ) has already been synthesised using coordination chemistry, and the other is hypothetical, where the dominant interaction is the spin–spin exchange interaction. Exact numerical diagonalisation methods have been used. Some non-trivial features, like nonmonotonicity of threshold temperatures with external magnetic field, persistence of multipartite entanglement and QD over bipartite entanglement, h...

In this paper, we discuss the possibility of imaging molecular orbitals from photoelectron spectra obtained via Laser Induced Electron Diffraction (LIED) in linear molecules. This is an extension of our work published recently in Physical Review A \textbf{94}, 023421 (2016) to the case of the HOMO-1 orbital of the carbon dioxide molecule. We show that such an imaging technique has the potential to image molecular orbitals at different internuclear distances in a sub-femtosecond time scale and with a resolution of a fraction of an Angstr\"om.

Coherent dynamics of localised π-electron rotations in an aromatic ring molecule may play an important role in designing next generation photo-induced organic molecular devices. In this paper, we present a theoretical study of laser control of localised π-electron rotations in a low symmetry aromatic ring molecule, which are created by the coherence of two or more electronic excited states. The control scenario is to manipulate energy spacings between two electronic states by utilising AC Stark shift induced by strong non-resonant ultraviolet (UV) laser. We set three targets for laser manipulation of localised electron rotational dynamics for (P)-2,2′-biphenol with two aromatic rings. The first target is flipping of the direction of the localised π-electron rotation on the same ring, the second one is the transfer of the π-electron rotation localisation from one aromatic ring to the other, and the third one is freezing the unidirectional π-electron rotation localised on one aromatic ring. We propo...

Fragment embedding approaches offer the possibility of accurate description of strongly correlated systems with low-scaling computational expense. In particular, wave function embedding approaches have demonstrated the ability to subdivide systems across highly entangled regions, promising wide applicability for a number of challenging systems. In this paper, we focus on the wave function embedding method Bootstrap Embedding, extending it to the Pariser–Parr–Pople and 2D Hubbard models in order to evaluate the behaviour of the method in systems that are less amenable to local fragment embedding. We find that Bootstrap Embedding remains accurate for these systems, and we investigate how fragment size, shape, and choice of matching conditions affect the results. We also evaluate the properties of Bootstrap Embedding that lead to the method's favourable convergence properties. Keywords: Embedding; correlation; Bootstrap; DMET, National Science Foundation (U.S.) (Grant CHE-1464804)

Ionic liquids have a great potential in capture and separation of carbon dioxide (CO2), and the solubility of CO2 in ionic liquids is one of key data for engineering applications. In this paper, th...

Density functional theory and the non-equilibrium Green's function are combined to investigate the co-modulation effect of endohedral Au atom and anchor S atoms on C20. In this paper, anchor atoms ...

By using genetic algorithm combined with B3LYP and QCISD methods, this paper investigates the stabilities and electronic structures of Al6OMm (M = Na, K; m = 2,4,6) and a few other AlnXNam (X = C, ...

Neural network algorithms are gradually applied to the field of chemical informatics. In this paper, the neural network models are used to predict the properties of compounds based on Molecular Inf...

In this paper, Rh-doped S-vacancy PtS2 (Rh-PtS2) monolayer is proposed as a novel sensing material for SOF2 detection in order to evaluate the operation status of SF6 insulation devices. The Rh dop...

The now classic Foldy–Wouthuysen transformation (FWT) was introduced as successive unitary transformations. This fundamental idea has become the standard in later developments such as the Douglas–Kroll transformation (DKT) – but it is not the only possibility. FWT can be seen as a simple special case of the general Van Vleck transformation (VVT) which besides the successive version has another, known as the canonical because of a series of nice mathematical properties discovered gradually over time. The aim of the present paper is to compare the two approaches – which give identical results in the lower orders, but not in the higher. After having recapitalised both, we apply them to Dirac's Hamiltonian for the electron in a constant electromagnetic field, written with so few assumptions about the operators that the mathematical techniques stand out separated from the terminology of relativistic quantum mechanics. FWT for a free particle is dealt with by a recent geometric approach to VVT. The orig...

The detailed structure and clustering free energy of aerosol particles are important for understanding of new particle formation from molecules and ions in the atmosphere. In this paper, configurations of the H2SO4 ·HSO−4 dimer were sampled with meta-dynamics aided ab initio molecular dynamics (MTD-AIMD) simulations. Based on the rigid rotor harmonic oscillator (RRHO) approximation and the law of mass action, the binding free energies (ΔG) of the dimer in the most stable configuration were calculated for three atmospheric circumstances, i.e. at the ground level and in the middle and upper troposphere. The results show that, the most stable H2SO4 ·HSO−4 dimer is combined via triple O–H⋅⋅⋅O hydrogen bonds. It can be generated efficiently in both the middle and upper troposphere, but not at the ground level. All our simulations were carried out at the level of hybrid density functional theory (PBE0, hybrid-DFT), which is more accurate than DFT only.

Periplasmic binding protein-dependent maltose transport system (MBP-MalFGK2) of Escherichia coli, an important member of the Adenosine triphosphate-binding cassette transporter superfamily, is in charge of the transportation of maltoses across cellular membrane. Studies have shown that this transport processes are activated by the binding of maltose and are accompanied by large-scale cooperative movements between different domains which are mediated by a network of important residues related to signal transduction and allosteric regulation. In this paper, the functionally crucial residues and long-range allosteric pathway of the regulation of the system by substrate were identified by utilising a coarse-grained thermodynamic method proposed by our group. The residues whose perturbations markedly change the binding free energy between maltoses and MBP-MalFGK2 were considered to be key residues. In result, the key residues in 62 clusters distributed in different subdomains were identified successful...