Program for the graphical construction of the total and difference electron density distribution maps for molecules by means of wave functions calculated by the MO LCAO method

1977 ◽  
Vol 17 (4) ◽  
pp. 624-624
Author(s):  
T. S. Zyubina ◽  
N. M. Klimenko ◽  
G. I. Pasechnik ◽  
A. S. Zyubin ◽  
O. P. Charkin
Keyword(s):  
Density Distribution ◽  
Electron Density ◽  
Electron Density Distribution ◽  
Wave Functions ◽  
Difference Electron Density ◽  
Distribution Maps ◽  
Graphical Construction

Electron Density Distribution Obtained from X-Ray Powder Data by the Maximum Entropy Method

1991 ◽  
Vol 35 (A) ◽  
pp. 77-83 ◽  
Author(s):  
Makoto Sakata ◽  
Masaki Takata ◽  
Yoshiki Kubota ◽  
Tatsuya Uno ◽  
Shintaro Kuhazawa ◽  
...  
Keyword(s):  
Density Distribution ◽  
Maximum Entropy ◽  
Electron Density ◽  
Diffraction Data ◽  
Electron Density Distribution ◽  
Maximum Entropy Method ◽  
Entropy Method ◽  
Nuclear Density ◽  
X Ray ◽  
Distribution Maps

AbstractThe electron density distribution maps for CaF2 and TiO2 (rutile) were obtained from profile fitting of powder diffraction data by a Maximum Entropy Method (MEM) analysis. The resultant electron density maps show clearly the nature of the chemical bonding. In order to interpret the results, the nuclear density distribution was also obtained for rutile from powder neutron diffraction data. In the electron density map for rutile obtained by HEM analysis from the X-ray data, both apical and equatorial bonding can be seen. On the other hand, the nuclear density of rutile Is very simple and shows the thermal vibration of nuclei.

scholarly journals Differenzelektronendichte im gefalteten 2 π-aromatischen System eines 1,3-Dihydro-1,3-diborets / Difference Electron Density in a Folded 2π-Aromatic System of a 1,3-Dihydro-1,3-diborete

1991 ◽  
Vol 46 (12) ◽  
pp. 1621-1624 ◽  
Author(s):  
Hermann Irngartinger ◽  
Jürgen Hauck ◽  
Walter Siebert ◽  
Manfred Hildenbrand
Keyword(s):  
Crystal Structure ◽  
Density Distribution ◽  
Electron Density ◽  
Electron Density Distribution ◽  
Ring System ◽  
Membered Ring ◽  
Aromatic System ◽  
Difference Electron Density ◽  
Folding Angle

The crystal structure and the X—X difference electron density distribution of 1,3-bis(diisopropylamino)-1,3,dihydro-1,3-diborete (1) has been determined at the temperature of 107 K. Both π-electrons of the folded aromatic four membered ring system (folding angle 47.6°) are uniformly distributed on the four ring bonds with equal lengths (B—C 1.524 A). These bonds are significantly bent.

Novel study on the electron density distribution projection maps calculated via the discrete cosine transform

2021 ◽  
Vol 54 (4) ◽  
Author(s):  
Hideo Hiraguchi
Keyword(s):  
Fourier Transform ◽  
Density Distribution ◽  
Internal Structure ◽  
Electron Density ◽  
Discrete Cosine Transform ◽  
Electron Density Distribution ◽  
Least Squares Method ◽  
Real Crystal ◽  
Cosine Transform ◽  
Distribution Maps

It is already known that a curve estimated via the discrete cosine transform (DCT) always passes through all the measured points without using imaginary numbers in the DCT coefficients, unlike the discrete Fourier transform. Moreover, owing to its character, the DCT can be used instead of the nonlinear least-squares method to express various theoretical curves. Because the DCT is a kind of Fourier transform, there is a possibility that the DCT could be employed to draw electron density distribution maps of crystals. If so, the probability that the DCT could be used to investigate the internal structure of materials by analysing the theoretical curves would increase. This article reports an attempt to draw the electron density distribution maps of the Mg3BN3 low-pressure phase [Mg3BN3(L)] by using the DCT in order to confirm the utility of the DCT for analysing the internal structure of materials. It is found that the DCT can provide mirror-symmetric electron density distribution projection maps and a modified DCT can be used to calculate whole standard electron density distribution projection maps for the surface plane of the unit cell. Moreover, a real crystal structure that has a centre of symmetry can be determined by the DCT by transforming a 1/4 part of the mirror-symmetric electron density distribution projection map.

A study on α-RuCl3 crystal structure by scanning tunneling microscopy

1989 ◽  
Vol 47 ◽  
pp. 30-31
Author(s):  
H.-J. Cantow ◽  
H. Hillebrecht ◽  
S. Magonov ◽  
H. W. Rotter ◽  
G. Thiele
Keyword(s):  
Crystal Structure ◽  
Density Distribution ◽  
Scanning Tunneling Microscopy ◽  
Electron Density ◽  
Structure Determination ◽  
Electron Density Distribution ◽  
Scanning Tunneling ◽  
Monoclinic Space Group ◽  
Tunneling Microscopy ◽  
X Ray

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.

X-ray emission and X-ray photoelectron studies of electron density distribution in Cu(II) complexes with 2-imidazoline nitroxides

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