Vladimir G. Tsirelson

Bio: Vladimir G. Tsirelson is an academic researcher from D. Mendeleev University of Chemical Technology of Russia. The author has contributed to research in topics: Electron density & Chemical bond. The author has an hindex of 35, co-authored 173 publications receiving 4465 citations. Previous affiliations of Vladimir G. Tsirelson include University of Augsburg & South Ural State University.

WinXPRO: a program for calculating crystal and molecular properties using multipole parameters of the electron density

Abstract: The computer program WinXPRO enables the calculation of crystal and molecular properties using the multipole parameters of the electron density. The list of properties includes the electron density and its topological and electric field characteristics, the local kinetic and potential energies, the electron localization function, and the effective crystal potential. WinXPRO works under the Windows operating system and can utilize any existing graphics program to display output.

Intermolecular hydrogen bond energies in crystals evaluated using electron density properties: DFT computations with periodic boundary conditions

Abstract: The hydrogen bond (H-bond) energies are evaluated for 18 molecular crystals with 28 moderate and strong O-H···O bonds using the approaches based on the electron density properties, which are derived from the B3LYP/6-311G** calculations with periodic boundary conditions. The approaches considered explore linear relationships between the local electronic kinetic G(b) and potential V(b) densities at the H···O bond critical point and the H-bond energy E(HB). Comparison of the computed E(HB) values with the experimental data and enthalpies evaluated using the empirical correlation of spectral and thermodynamic parameters (Iogansen, Spectrochim. Acta Part A 1999, 55, 1585) enables to estimate the accuracy and applicability limits of the approaches used. The V(b)-E(HB) approach overestimates the energy of moderate H-bonds (E(HB) < 60 kJ/mol) by ~20% and gives unreliably high energies for crystals with strong H-bonds. On the other hand, the G(b)-E(HB) approach affords reliable results for the crystals under consideration. The linear relationship between G(b) and E(HB) is basis set superposition error (BSSE) free and allows to estimate the H-bond energy without computing it by means of the supramolecular approach. Therefore, for the evaluation of H-bond energies in molecular crystals, the G(b) value can be recommended to be obtained from both density functional theory (DFT) computations with periodic boundary conditions and precise X-ray diffraction experiments.

The chemical bond and atomic displacements in SrTiO3 from X‐ray diffraction analysis

Abstract: The deformation electron-density (dynamic Fourier) maps and the anharmonicity of atomic displacements in strontium titanate, SrTiO 3 (Gram-Charlier model), were studied by high-precision single-crystal X-ray diffraction analysis at 145(1) and 296(2) K. Space group Pm3m, cubic, λ(Mo Kα) = 0.71069 A, Z = 1, F(000) = 84, T = 145 (1)K, a = 3.8996(5)A, V = 59.30(2)A 3 , D x = 5.138(2) g cm -3 , μ = 26.778 mm -1 , R = 0.0063, wR = 0.0040, S = 1.05 for 131 unique reflections and T = 296(2)K, a = 3.901(1)A, V = 59.36(5)A 3 , D x = 5.133(4) g cm -3 , μ = 26.700 mm -1 , R = 0.0071, wR = 0.0050, S = 1.40 for 109 unique reflections. Strong anharmonicity of the atomic displacements was observed for all atoms at 145 K and for Ti and O atoms at 296 K. These are explained by a model in which electronic instability in the TiO 6 octahedron leads to a displacement of the Ti atom from the center of the octahedron, and the lattice instability resulting from the consequent stretching of the Sr-O bonds leads to a rotation of the octahedra. Both distortions show only short-range order at the temperature studies, but show indications of freezing out as the temperature is lowered towards the rotational phase transition at 106 K. The experimental dynamic Fourier deformation electron-density maps and the Hirshfeld atomic charges were calculated

Multipole analysis of the electron density in triphylite, LiFePO4, using X-ray diffraction data

Abstract: The electron density distribution and 3d-orbital electron occupancies for the Fe atom in synthetic triphylite, LiFePO 4 , have been analysed using single-crystal X-ray diffraction data measured at T=298 K with Mo Kα (λ=0.71069 A) radiation to a resolution corresponding to (sin θ max /λ)=1.078 A -1 . Measurements of 3265 reflections gave 944 unique data [R int (I)=0.036] with I>2σ(I). For an atomic multipole density model fitted by least-squares methods R(F)=0.0174 for all unique reflections. The Fe atom 3d-orbital occupancies have been derived from the multipole population coefficients using point-group-specific relations

Multiwfn: a multifunctional wavefunction analyzer.

Abstract: Multiwfn is a multifunctional program for wavefunction analysis. Its main functions are: (1) Calculating and visualizing real space function, such as electrostatic potential and electron localization function at point, in a line, in a plane or in a spatial scope. (2) Population analysis. (3) Bond order analysis. (4) Orbital composition analysis. (5) Plot density-of-states and spectrum. (6) Topology analysis for electron density. Some other useful utilities involved in quantum chemistry studies are also provided. The built-in graph module enables the results of wavefunction analysis to be plotted directly or exported to high-quality graphic file. The program interface is very user-friendly and suitable for both research and teaching purpose. The code of Multiwfn is substantially optimized and parallelized. Its efficiency is demonstrated to be significantly higher than related programs with the same functions. Five practical examples involving a wide variety of systems and analysis methods are given to illustrate the usefulness of Multiwfn. The program is free of charge and open-source. Its precompiled file and source codes are available from http://multiwfn.codeplex.com.

VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data

Abstract: VESTA is a three-dimensional visualization system for crystallographic studies and electronic state calculations. It has been upgraded to the latest version, VESTA 3, implementing new features including drawing the external mor­phology of crystals; superimposing multiple structural models, volumetric data and crystal faces; calculation of electron and nuclear densities from structure parameters; calculation of Patterson functions from structure parameters or volumetric data; integration of electron and nuclear densities by Voronoi tessellation; visualization of isosurfaces with multiple levels; determination of the best plane for selected atoms; an extended bond-search algorithm to enable more sophisticated searches in complex molecules and cage-like structures; undo and redo in graphical user interface operations; and significant performance improvements in rendering isosurfaces and calculating slices.

Electronically conductive phospho-olivines as lithium storage electrodes

Abstract: Lithium transition metal phosphates have become of great interest as storage cathodes for rechargeable lithium batteries because of their high energy density, low raw materials cost, environmental friendliness and safety. Their key limitation has been extremely low electronic conductivity, until now believed to be intrinsic to this family of compounds. Here we show that controlled cation non-stoichiometry combined with solid-solution doping by metals supervalent to Li+ increases the electronic conductivity of LiFePO4 by a factor of approximately 10(8). The resulting materials show near-theoretical energy density at low charge/discharge rates, and retain significant capacity with little polarization at rates as high as 6,000 mA x g(-1). In a conventional cell design, they may allow development of lithium batteries with the highest power density yet.

The Halogen Bond

Abstract: The halogen bond occurs when there is evidence of a net attractive interaction between an electrophilic region associated with a halogen atom in a molecular entity and a nucleophilic region in another, or the same, molecular entity. In this fairly extensive review, after a brief history of the interaction, we will provide the reader with a snapshot of where the research on the halogen bond is now, and, perhaps, where it is going. The specific advantages brought up by a design based on the use of the halogen bond will be demonstrated in quite different fields spanning from material sciences to biomolecular recognition and drug design.