Effective Molecular Dynamics Model of Ionic Solutions for Large-Scale Calculations

A model of ionic solutions is proposed which can be used to calculate aqueous salt solutions in different nanostructures. The interaction potential of the model includes the Lennard-Jones potential and angularly averaged dipole–dipole and ion–dipole interactions. Lennard-Jones potential parameters for different ions are obtained. Characteristics of aqueous solutions at different salt concentrations are calculated using the molecular dynamics method. It is shown that the calculated values of the hydration shells of ions parameters are in good agreement with the theoretical and experimental data at a salt concentration of 1 mol/kg. The computational scheme used in the calculations is described. It is shown that calculations using the proposed model require less computing resources compared with the standard models of ionic solutions.     

Quasi-Isentropic Compressibility of Deuterium at a Pressure of ~12 TPa

An experimental result for the quasi-isentropic compressibility of a strongly nonideal deuterium plasma compressed in a spherical device by the pressure P = 11400 GPa (114 Mbar) to the density ρ ≈ 10g/cm³ has been reported. The characteristics of the experimental device, diagnostic methods, and experimental results have been described. The trajectory of motion of metallic shells compressing a deuterium plasma has been recorded using intense pulsed sources of X rays with the boundary energy of electrons up to 60 MeV. The deuterium plasma density ρ ≈ 10g/cm³ has been determined from the measured radius of the shell at the time of its “stop.” The pressure of the compressed plasma has been determined from gas-dynamic calculations taking into account the real characteristics of the experimental device.     

Distribution of interstitial atoms over octahedral pores of ordered alloys with CuAu structure

The authors consider the kinetics of processes of redistributions of interstitial atoms over the octahedral interstices in ordered alloys of the CuAu type as a result of a sudden change in temperature. The relaxation time of the process is determined and the equilibrium concentrations of interstitial atoms are found. These quantities are considered as functions of the degree of long-range order, the alloy composition, and the temperature.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 105–109, March, 1977.     

Electronic structure and experimental spectra of some rare-earth oxyfluorides

The results of electronic structure calculations on LaOF, PrOF, NdOF and EuOF making use of the Xα discrete variational method are presented, together with experimental X-ray photoelectron and emission spectra of these compounds. The MO energy-level diagrams provide a satisfactory semiquantitative interpretation of the experimental XPS, X-ray emission, and luminescence spectra.     

Analysis of Transformer Oil Using IR Analyzers

Spectral characteristics of samples of transformer oil that differ in technical grade, service life, and content of an antioxidant additive and dissolved water are investigated. It is suggested to determine service deterioration of insulating oils from absorption in the region 1710 cm^–1 using IR filter analyzers.     

Theory of a surface phase transformation induced by impurity atoms in binary alloys containing interstitial impurity atoms

Mutual influence of the surface segregation of atoms on lattice sites and in interstitials is studied in the self-consistent field approximation. The effect of occurrence of a local surface phase transformation is predicted, which is caused by a local loss of stability of the statistical distribution of atoms of components on the surface due to the presence of interstitial impurity atoms. A theory is constructed for an induced phase transformation for [001] plane of a single crystal of a binary alloy with an fcc lattice whose octahedral interstitials are occupied by interstitial atoms.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 50–55, September, 1984.     

Angular distribution of 4.43-MeV γ-rays produced in inelastic scattering of 14.1-MeV neutrons by <Superscript>12</Superscript>C nuclei

The work is devoted to measuring the angular distribution of 4.43-MeV γ-rays produced in inelastic scattering of 14.1-MeV neutrons by ¹²C nuclei. A portable ING-27 neutron generator (designed and fabricated at VNIIA, Moscow) with a built-in 64-pixel silicon α-detector was used as a source of tagged neutrons. The γ-rays of characteristic nuclear radiation from ¹²C were detected with a spectrometric system that consisted of 22 γ-detectors based on NaI(Tl) crystals arranged around the carbon target. The measured angular distribution of 4.43-MeV γ-rays is analyzed and compared with the results of other published experimental works.     

Role of relativistic effects in the electronic structure and chemical bond of lead hexacyanoferrate

The electronic structure of a large fragment of the Pb₂Fe(CN)₆ crystal lattice with the trigonal structure is studied in the framework of a fully relativistic discrete variational cluster method. On the basis of comparing the results obtained with the data of previous non-relativistic calculations we have considered the relativistic effects on the electronic energy spectrum, the charge density distribution, and Pb-N, N-C, and C-Fe chemical bonding.