scholarly journals PolaBer: a program to calculate and visualize distributed atomic polarizabilities based on electron density partitioning

2014 ◽  
Vol 47 (4) ◽  
pp. 1452-1458 ◽  
Author(s):  
Anna Krawczuk ◽  
Daniel Pérez ◽  
Piero Macchi

This paper describes the program PolaBer, which calculates atomic polarizability tensors from electric field perturbations of a partitioned electron density distribution. Among many possible partitioning schemes, PolaBer is currently using the quantum theory of atoms in molecules and it is interfaced to programs that apply such a partitioning. The calculation of the atomic tensors follows the idea suggested by Keith [The Quantum Theory of Atoms in Molecules: From Solid State to DNA and Drug Design, (2007), edited by C. F. Matta & R. J. Boyd. Weinheim: Wiley-VCH], which enables the removal of the intrinsic origin dependence of the atomic charge contributions to the molecular dipole moment. This scheme allows the export, within chemically equivalent functional groups, of properties calculated from atomic dipoles, such as for example the atomic polarizabilities. The software permits visualization of the tensors and calculation of straightforward optical properties of a molecule (like the molar refractive index) or a crystal (assuming the molecule in a given crystal lattice).

Author(s):  
Наталья Петровна Русакова ◽  
Георгий Александрович Курочкин ◽  
Юлия Ивановна Софронова ◽  
Владимир Владимирович Туровцев

Изучено распределение электронной плотности 14 циклических соединений и одного нециклического. Проведен анализ зарядов и объемов групп, найдены группы доноры и акцепторы электронной плотности. Рассмотрено изменение электронной плотности серосодержащих групп под влиянием окружения. The electron density distribution of 14 cyclic compounds and one non-cyclic compound was studied. The group charges and group volumes were analyzed, and the electron density donor and acceptor groups were found. Changes in the electronic density of sulfur-containing groups under the influence of the environment are considered.


Author(s):  
Александр Витальевич Зиганшин ◽  
Наталья Петровна Русакова ◽  
Владимир Владимирович Туровцев ◽  
Юрий Димитриевич Орлов

Методом B3LYP получено распределение электронной плотности ρ(r) 15-краун-5 и его серосодержащих аналогов: 1-тио-15-краун-5, 1,4-дитио-15-краун-5, 1,4,7-тритио-15-краун-5, 1,4,7,10-тетратио-15-краун-5, 1,4,7,10,13-пентатио-15-краун-5. Вычислены групповые интегральные характеристики распределения ρ(r) соединений в рамках «квантовой теории атомов в молекулах» QTAIM. Рассмотрены внутримолекулярные слабые взаимодействия в 1,4-дитио-15-краун-5, 1,4,7-тритио-15-краун-5, 1,4,7,10-тетратио-15-краун-5, 1,4,7,10,13-пентатио-15-краун-5 и отмечено образование клеточной структуры в 1,4,7-тритио-15-краун-5. Electron density distribution of 15-crown-5 and its sulfur-containing analogs: 1-thio-15-crown-5, 1,4-dithio-15-crown-5, 1,4,7-threetio-15-crown-5, 1,4,7,10-tetratio-15-crown-5, 1,4,7,10,13-pentatio-15-crown-5 by the B3LYP method was obtained. The charges, volumes and electronic energies of the compounds are calculated in the postulates of the «quantum theory of atoms in molecules» (QTAIM). Intramolecular weak interactions are found in the 1,4-dithio-15-crown-5, 1,4,7-threetio-15-crown-5, 1,4,7,10-tetratio-15-crown-5, 1,4,7,10,13-pentatio-15-crown-5. The cell structure is formed in 1,4,7-threetio-15-crown-5.


Author(s):  
Bürgehan Terlan ◽  
Lev Akselrud ◽  
Alexey I. Baranov ◽  
Horst Borrmann ◽  
Yuri Grin

Binary vanadium borides are suitable model systems for a systematic analysis of the transferability concept in intermetallic compounds due to chemical intergrowth in their crystal structures. In order to underline this structural relationship, topological properties of the electron density in VB, V3B4 and VB2 reconstructed from high-resolution single-crystal X-ray diffraction data as well as derived from quantum chemical calculations, are analysed in terms of Bader's Quantum Theory of Atoms in Molecules [Bader (1990). Atoms in Molecules: A Quantum Theory, 1st ed. Oxford: Clarendon Press]. The compounds VB, V3B4 and VB2 are characterized by a charge transfer from the metal to boron together with two predominant atomic interactions, the shared covalent B—B interactions and the polar covalent B—M interactions. The resembling features of the crystal structures are well reflected by the respective B—B interatomic distances as well as by ρ(r) values at the B—B bond critical points. The latter decrease with an increase in the corresponding interatomic distances. The B—B bonds show transferable electron density properties at bond critical points depending on the respective bond distances.


Author(s):  
Marcin Stachowicz ◽  
Maura Malinska ◽  
Jan Parafiniuk ◽  
Krzysztof Woźniak

On the basis of a multipole refinement of single-crystal X-ray diffraction data collected using an Ag source at 90 K to a resolution of 1.63 Å−1, a quantitative experimental charge density distribution has been obtained for fluorite (CaF2). The atoms-in-molecules integrated experimental charges for Ca2+and F−ions are +1.40 e and −0.70 e, respectively. The derived electron-density distribution, maximum electron-density paths, interaction lines and bond critical points along Ca2+...F−and F−...F−contacts revealed the character of these interactions. The Ca2+...F−interaction is clearly a closed shell and ionic in character. However, the F−...F−interaction has properties associated with the recently recognized type of interaction referred to as `charge-shift' bonding. This conclusion is supported by the topology of the electron localization function and analysis of the quantum theory of atoms in molecules and crystals topological parameters. The Ca2+...F−bonded radii – measured as distances from the centre of the ion to the critical point – are 1.21 Å for the Ca2+cation and 1.15 Å for the F−anion. These values are in a good agreement with the corresponding Shannon ionic radii. The F−...F−bond path and bond critical point is also found in the CaF2crystal structure. According to the quantum theory of atoms in molecules and crystals, this interaction is attractive in character. This is additionally supported by the topology of non-covalent interactions based on the reduced density gradient.


1996 ◽  
Vol 74 (6) ◽  
pp. 976-987 ◽  
Author(s):  
Christof Hättig ◽  
Bernd A. Hebβ ◽  
Georg Jansen ◽  
János G. Ángyán

Frequency-dependent distributed polarizabilities have been determined from time-dependent Hartree–Fock calculations, using the partitioning of the molecular space suggested by Bader's topological theory of atoms in molecules. The basis set dependence of the distributed dynamic polarizabilities is analyzed in terms of the first few Cauchy moments, for the carbon monoxide, water, cyanogen, urea and benzene molecules. Two alternative relocalization schemes have been considered in order to reduce the number of distributed dynamic polarizability parameters. The first one, closely related to the atomic polarizability model of Bader, leads to atomic charge–dipole and dipole–dipole polarizabilities, describing the response of the molecular charge distribution to a uniform external field, in terms of atomic charges and dipoles. The second scheme, similar to that suggested by Stone, retains the fully distributed description of the dynamic charge-flow polarizabilities, while all two-center dipole–dipole and charge–dipole contributions are condensed in one-center dynamic dipole–dipole polarizabilities. Key words: Bader-partitioning, distributed dynamic polarizabilities, Cauchy-moments, benzene, polarizability of; urea, polarizability of.


1994 ◽  
Vol 49 (3) ◽  
pp. 522-524
Author(s):  
Valentin P. Feshin ◽  
Yurii E. Sapozhnikov ◽  
Vasilii V. Shchepin ◽  
Irina Yu. Petukhova ◽  
Arsenii D. Gordeev ◽  
...  

Abstract The 35Cl NQR frequencies and EFG asymmetry parameters at the 35Cl nuclei have been mea­sured for compounds of the series 4-XC6H4MCCl2C(O)C6H5 (M = S and Se, X = H and CH3) at 77 K. The electron distribution at the Cl atoms in all the compounds studied differs from axial symmetry, and is unequal for the two Cl atoms of the CCl2 group. The results of the measurements imply pσ-electron density nonequivalence of Cl atoms in the CCl2 group of these molecules.


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