scholarly journals Die zeitliche Änderung der radialen Elektronendichteverteilung beim Theta-Pinch

1963 ◽  
Vol 18 (8-9) ◽  
pp. 895-900
Author(s):  
Franz Peter Küpper
Keyword(s):  
Density Distribution ◽  
Electron Density ◽  
Electron Density Distribution ◽  
Electron Distribution ◽  
Radial Symmetry ◽  
Zero Order ◽  
Time Interval ◽  
Interferometric Method ◽  
Density Distributions ◽  
Theta Pinch

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.

Elektronenkorrelationseffekte in der Elektronendichteverteilung von Stickstoff und Acetylen / Effects of Electron Correlation in the Electron Density Distribution of Nitrogen and Acetylene

1978 ◽  
Vol 33 (2) ◽  
pp. 245-246
Author(s):  
Hans-Lothar Hase ◽  
Karl-Wilhelm Schulte ◽  
Armin Schweig
Keyword(s):  
Density Distribution ◽  
Electron Density ◽  
Electron Correlation ◽  
Electron Density Distribution ◽  
Electron Distribution ◽  
Lone Pair ◽  
General Interest ◽  
Atomic Core ◽  
Difference Density ◽  
Ci Calculations

It is shown by AHF-CI calculations that the changes in the electron distribution in bonding and lone pair regions of nitrogen and acetylene due to electron correlation can be neglected when calculating electron difference densities of these molecules. The changes brought about by electron correlation are such that the electron density in interatomic regions is reduced and in atomic (core) regions increased. These results might meet general interest in the area of electron difference density determinations.

PROTON MAGNETIC RESONANCE SHIFTS AND THE ELECTRON DENSITY DISTRIBUTION IN AROMATIC SYSTEMS

1963 ◽  
Vol 41 (4) ◽  
pp. 966-982 ◽  
Author(s):  
T. Schaefer ◽  
W. G. Schneider
Keyword(s):  
Density Distribution ◽  
Electron Density ◽  
Electron Density Distribution ◽  
Excess Charge ◽  
Good Correspondence ◽  
Calculated Density ◽  
Density Distributions ◽  
Aromatic Molecules ◽  
Aromatic Ions ◽  
Density Values

The quantitative nature of the empirical linear correlation between the proton resonance shifts in aromatic molecules and the local electron density on the carbon atom to which the proton is bonded has been investigated. The application of this relationship to the determination of the electron density distribution of a variety of aromatic molecules, as well as the main limitations inherent in this application, are discussed. Electron density distributions have been derived for aniline, anisole, azulene, acepleiadylene, pyridine, pyridinium ion, and for the aromatic ions pentalenyl, indenyl, fluorenyl, triphenylmethyl cation, and azulene dianion, and are compared with those calculated by molecular orbital methods. In general there is a fairly good correspondence between the experimental and calculated density values, although for the aromatic ions the excess charge tends to be somewhat more uniformly distributed over the molecule than would be indicated by simple MO calculations.

Spatial Electron Density Distribution of Chlorine Atoms in Molecules of the Series 4-XC6H4MCCl2C(O)C6H5 (M = S and Se)

1994 ◽  
Vol 49 (3) ◽  
pp. 522-524
Author(s):  
Valentin P. Feshin ◽  
Yurii E. Sapozhnikov ◽  
Vasilii V. Shchepin ◽  
Irina Yu. Petukhova ◽  
Arsenii D. Gordeev ◽  
...  
Keyword(s):  
Density Distribution ◽  
Electron Density ◽  
Axial Symmetry ◽  
Electron Density Distribution ◽  
Electron Distribution ◽  
Atoms In Molecules ◽  
Chlorine Atoms ◽  
Asymmetry Parameters ◽  
Cl Atoms

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.

A 15N and 13C N.M.R. study of electron distribution in Di- and Tri-azapentadienium salts

1978 ◽  
Vol 31 (5) ◽  
pp. 1005 ◽  
Author(s):  
AJ Jones ◽  
H McNab ◽  
P Hanisch
Keyword(s):  
Density Distribution ◽  
Electron Density ◽  
Electron Density Distribution ◽  
Electron Distribution ◽  
Chemical Shifts ◽  
Phenyl Group ◽  
Natural Abundance ◽  
Fourier Methods ◽  
13C Chemical Shifts ◽  
Electron Withdrawal

The 15N and 13C chemical shifts of eight vinamidinium and azavinamidinium cations have been determined at the natural-abundance level by means of Fourier methods. Both 15N and 13C chemical shifts reflect the electron- density distribution in the pentadienium chain, especially in the aryl derivatives in which conjugative stabilization through electron withdrawal by the substituent phenyl group is exhibited.

Quantitative Description of the pB and Electron Density Distributions around the Inferred Neutral Line

1994 ◽  
Vol 144 ◽  
pp. 427-430
Author(s):  
M. Guhathakurta
Keyword(s):  
Density Distribution ◽  
Current Sheet ◽  
Electron Density ◽  
Electron Density Distribution ◽  
Neutral Line ◽  
Quantitative Description ◽  
Three Dimensional ◽  
Density Distributions ◽  
Dimensional Distribution

AbstractWe have investigated the three-dimensional distribution of the polarization brightness product (pB) and inferred the electron density distribution relative to the heliographic current sheet during the declining phase of cycle 20 (1973-1976). From the study we observe that the polar and current sheet densities do not vary during the last third of the cycle.

Thermalisierung und zeitliche Entwicklung der Elektronendichte und Temperatur von Funkenkanälen in Wasserstoff

1970 ◽  
Vol 25 (3) ◽  
pp. 420-429 ◽  
Author(s):  
H. Tholl
Keyword(s):  
Density Distribution ◽  
Electron Density ◽  
Electron Density Distribution ◽  
Discharge Channel ◽  
Diagnostic Methods ◽  
Plasma Diagnostic ◽  
Density Distributions ◽  
Maximum Electron Density ◽  
Zeitliche Entwicklung ◽  
Further Development

In a streamer initiated pre-discharge channel in H2 the axial and radial electron density distributions were measured at different times of the channel development. It was found that at any point in the channel where the electron density reaches ≅ 2 - 1017 cm-3 an immediate thermalisation of the plasma at this point takes place in a time of ≅ 10 nsec. Due to the inhomogeneous radial and axial electron density distribution in a streamer initiated discharge channel the thermalisation begins at first in a constricted region of the channel. The further development of the electron density and temperature distributions in the thermalized channel was studied by means of spectroscopic plasma diagnostic methods in channels initiated by different overvoltages. These experiments have shown that the inhomogeneous axial electron density distribution is equalized after a time of ≅ 100 nsec. The maximum electron density of ≅ 1 - 2 - 1018 cm-3 is reached in the channel axis immediately after the thermalisation of the channel whereas the temperature increases during the time of the highest energy input to the maximum of ≅ 5 - 6 • 104 °K

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.

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