Anisotropy of electron-density distribution around atoms in molecules: N, P, O and S atoms

1990 ◽  
Vol 205 ◽  
pp. 191-201 ◽  
Author(s):  
Shigeru Ikuta
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.


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):  
H.-J. Cantow ◽  
H. Hillebrecht ◽  
S. Magonov ◽  
H. W. Rotter ◽  
G. Thiele

From X-ray analysis, the conclusions are drawn from averaged molecular informations. Thus, limitations are caused when analyzing systems whose symmetry is reduced due to interatomic interactions. In contrast, scanning tunneling microscopy (STM) directly images atomic scale surface electron density distribution, with a resolution up to fractions of Angstrom units. The crucial point is the correlation between the electron density distribution and the localization of individual atoms, which is reasonable in many cases. Thus, the use of STM images for crystal structure determination may be permitted. We tried to apply RuCl3 - a layered material with semiconductive properties - for such STM studies. From the X-ray analysis it has been assumed that α-form of this compound crystallizes in the monoclinic space group C2/m (AICI3 type). The chlorine atoms form an almost undistorted cubic closed package while Ru occupies 2/3 of the octahedral holes in every second layer building up a plane hexagon net (graphite net). Idealizing the arrangement of the chlorines a hexagonal symmetry would be expected. X-ray structure determination of isotypic compounds e.g. IrBr3 leads only to averaged positions of the metal atoms as there exist extended stacking faults of the metal layers.


2006 ◽  
Vol 47 (3) ◽  
pp. 558-562 ◽  
Author(s):  
L. N. Mazalov ◽  
S. V. Trubina ◽  
G. K. Parygina ◽  
I. M. Oglezneva ◽  
E. A. Aseeva ◽  
...  

1963 ◽  
Vol 18 (8-9) ◽  
pp. 895-900
Author(s):  
Franz Peter Küpper

In a θ-pinch the radial symmetry of the electron density distribution as a function of time has been measured by a MACH—ZEHNDER interferometer. In a time interval of 400 nsec during a discharge an image converter made three pictures (exposure times of 10 nsec each) . Up to 100 nsec after the first compression, the experimental results show different density distributions for the cases of trapped parallel and antiparallel magnetic fields. Complete radial symmetry of the electron density distribution was not found.Another interferometric method for measuring the radial symmetry of the electron distribution by observing “zero order” fringes is described.


Sign in / Sign up

Export Citation Format

Share Document