Interband transitions in a spherical quantum layer in the presence of an electric field: Spherical rotator model

The interband transitions in a spherical GaAs quantum layer in the presence of an arbitrarily directed electric field are studied theoretically within the framework of the rigid spherical rotator model. The problem is solved under the assumption that the external field is a perturbation. Within the framework of the dipole approximation an expression for the interband absorption coefficient is obtained, and the absorption threshold frequency is determined. The corresponding selection rules are derived. A comparison with the case of quantum transitions in a spherical quantum layer in the presence of a radial electric field is performed.     

Variation in magnesium isotopic composition during zone recrystallization of MgCl<Subscript>2</Subscript>·6H<Subscript>2</Subscript>O

The variation in Mg isotopic composition during MgCl₂·6H₂O zone recrystallization was studied. It was shown that light isotope ²⁴ Mg enrichment occurs at the crystal end to which the recrystallization zone moves. Isotopes ²⁵ Mg and ²⁶ Mg concentrate in the initial crystallization zone. When the molten zone is exposed to a de magnetic field or direct current, the separation factor increases. The data obtained were compared with data on magnesium isotope separation by other physicochemical methods.     

Nanoscale metal oxide particles produced in the plasma discharge in the liquid phase upon exposure to ultrasonic cavitation. 1. Method for producing particles

It is shown that a new form of the plasma discharge with bulk glow throughout the space between electrodes and an descending current-voltage characteristic, occurring in liquid in an ultrasonic field with an intensity above the cavitation threshold, can be efficiently used to initiate the various physical and chemical processes. In such an acoustic plasma discharge, nanoparticles of oxides of various metals, i.e., aluminum, copper, tin, iron, titanium, indium, zinc, molybdenum, and others, are synthesized with controllable particle shape and size and narrow size distribution. Micrographs of some nanoparticles are presented. The difference in luminescence of particles produced in the absence and presence of cavitation is shown.     

Effects of hydrostatic pressure on the donor impurity in a cylindrical quantum dot with Morse confining potential

The effects of hydrostatic pressure and size quantization on the binding energies of a hydrogen-like donor impurity in cylindrical GaAs quantum dot (QD) with Morse confining potential are studied using the variational method and effective-mass approximation. In the cylindrical QD, the effect of hydrostatic pressure on the binding energy of electron has been investigated and it has been found that the application of the hydrostatic pressure leads to the blue shift. The dependence of the absorption edge on geometrical parameters of cylindrical QD is obtained. Selection rules are revealed for transitions between levels with different quantum numbers. It is shown that for the radial quantum number, transitions are allowed between the levels with the same quantum numbers, and any transitions between different levels are allowed for the principal quantum number.     

Technologies of distributed data storage systems for numerical simulation of materials

A method for structuring experimental data for applications in software packages for simulating materials is considered. A unified transport file (UTF) is proposed for data exchange between network nodes. In the study of data structuring algorithms, the data retrieval rate in the storage system was estimated under conditions of increasing data base content.     

Diamagnetic susceptibility of the electron gas in the cylindrical nanolayer

Diamagnetic properties of the electron gas in cylindrical nanolayer have been investigated. The dependence of mean energy, mean magnetization and mean magnetic susceptibility on the values of magnetic field is obtained. Comparison of these dependencies with the case, when the electron gas is localized in the cylindrical quantum dot, is carried out. In a nanolayer, the character of an effect of size quantization on the magnetic properties of the electron gas has been revealed.     

Two Electron States in a Thin Spherical Nanolayer: Reduction to the Model of Two Electrons on a Sphere

Two electron states in a thin spherical nanolayer are discussed. Adiabatic approach is used to divide the system to fast (radial) and slow (angular) subsystems. This leads the Coulomb interaction to be dependent on angular variables, more precisely, on the relative angle between electrons. Approximated Coulomb interaction potential is discussed. Analytical solutions for angular part of Schrödinger equation as well as for energy spectrum for the case of harmonic approximation are obtained. Also the first order of correction energy is discussed by using perturbation theory. For the ground state an analytical expression for the first order correction energy dependent on effective radius of the nanolayer is obtained. Obtained results are compared with exact Coulomb interaction model presented by Loos and Gill.