Structure and Chemical Composition of Manganese-Doped GaSb Dislocations

Electron microscopic observations showed that the preparation of magnetic semiconductor GaSb〈Mn〉 by melt quenching is accompanied by discrete manganese precipitation on GaSb dislocations, this precipitation generating inclusions sized from a split micrometer to several micrometers. The chemical composition of microinclusions was determined by electron probe microanalysis. The superposition of the magnetic properties of compounds that are formed in the Mn–Sb system determines the magnetic properties of GaSb〈Mn〉.     

Avoiding singularity problems associated with meta-GGA (generalized gradient approximation) exchange and correlation functionals containing the kinetic energy density

Convergence problems of meta-GGA (generalized gradient approximation) XC (exchange and correlation) functionals containing a self-interaction correction term are traced back to a singularity of the latter that occurs at critical points of the electron density. This is demonstrated for the bond critical point of equilibrium and stretched H2. A simple remedy is suggested that cures meta-XC functionals such as VSXC, TPSS, M05, M06, and their derivatives without extra cost.     

Structure Constant and Grain Size Determination by Ferromagnetic Resonance in Thin Magnetic Films

Russian Physics Journal - The paper shows that the structure constant and the average crystal grain size of anisotropic nanocrystalline magnetic film can be determined by analyzing the shape of the...     

New way of describing static and dynamic deformations of the Jahn-Teller type in ring molecules

A new method is presented to describe deformations of an N-membered planar ring (N-ring) molecule in terms of deformation vectors that can be expressed by a set of 2N-3 deformation amplitudes and phase angles. The deformation coordinates are directly derived from the normal vibrational modes of the N-ring and referenced to a regular polygon (N-gon) of unit length. They extend the conceptual approach of the Cremer-Pople puckering coordinates (J. Am. Chem. Soc. 1975, 97, 1354) to the planar ring and make it possible to calculate, e.g., a planar ring of special deformation on a Jahn-Teller surface. It is demonstrated that the 2N-3 deformation parameters are perfectly suited to describe the pseudorotation of a bond through the ring as it is found in cyclic Jahn-Teller systems. In general, an N-membered planar ring can undergo N-2 different bond pseudorotations provided the energetics of such a process is feasible. The Jahn-Teller distortions observed in ring compounds correspond either directly to the basic pseudorotation modes or to linear combinations of them. Any deformed ring molecule can be characterized in terms of the new ring deformation coordinates, which help to identify specific electronic effects. The usefulness of the ring deformation coordinates is demonstrated by calculating the Jahn-Teller surfaces for bond pseudorotation in the case of the cyclopropyl radical cation and cyclobutadiene as well as the ring deformation surfaces of disulfur dinitride and its dianion employing multireference averaged quadratic coupled cluster (MR-AQCC) theory, equation-of-motion coupled cluster theory in form of EOMIP-CCSD, and single determinant coupled cluster theory in form of CCSD(T).     

Measurement of the polarization correlation parameter C nn in the pp elastic scattering with an unpolarized proton target and an unpolarized 1-GeV proton beam

The polarization correlation parameter C _nn in the elastic proton-proton scattering was for the first time measured with a high statistical accuracy at 1 GeV using an unpolarized proton beam incident on an unpolarized proton target. Both outgoing protons from the reaction were detected in coincidence by means of a two-arm focusing magnetic spectrometer installed at nonsymmetric angles corresponding to the center-of-mass scattering angle Θ_cm = 62.25°. The correlation parameter C _nn , as well as polarizations P ₁ and P ₂ of the secondary protons, were measured by means of multiwire proportional chamber polarimeters placed at the focal planes of each spectrometer arm. The obtained data are compared with the predictions of the phase-shift analysis. The connection with the experiment on C _nn and polarization measurements in the (p, 2p) reaction on ⁴He and other light nuclei in similar kinematics is discussed     

Effect of temperature on the region of residual rays of CdP2 and ZnP2 single crystals

The technology of growing tetragonal ZnP₂ and CdP₂ single crystals has been presented. The dielectric permittivity dispersion of tetragonal zinc and cadmium diphosphides in the region of residual rays has been studied, and its dependence on temperature has been scrutinized.