An Ellipsometric Investigation of the Optical Properties of Ru<Subscript>2</Subscript>Ge<Subscript>3</Subscript> and Ru<Subscript>2</Subscript>Sn<Subscript>3</Subscript> Compounds

Ellipsometric investigations of the optical properties of Ru₂Ge₃ and Ru₂Sn₃ intermetallic compounds are carried out in the wavelength range from 0.22 to 15 μm. The nature of interband light absorption is analyzed based on a comparative analysis of the experimental and theoretical frequency dependences of an optical conductivity. The obtained results confirm the existence of energy gaps at the Fermi level in the electronic spectra of these materials predicted earlier by the band-structure calculations.     

The even–odd effect in the dependence of optical anisotropy on the number of protons in complexing agent ions of liquid-crystal coordination compounds of lanthanides

The values of optical anisotropy of two series of thermotropic nematic liquid crystalline complexes based on the ions Eu⁺³, Gd⁺³, Tb⁺³, and Dy⁺³ have been determined. Even–odd alternation of optical anisotropy with an increasing number of protons in ions of lanthanides has been observed. It is established that, in the considered series of lanthanidomesogens, optical anisotropy is more sensitive to changes in the ligand structure of complexes than to the variation of the complexing agent.     

Role of Fe and Co in optical conductivity and electronic structure of TbNi4Fe and TbNi4Co

Optical properties of two intermetallic compounds TbNi₄Fe and TbNi₄Co have been studied employing ellipsometry in a spectral range 0.22–15 μm to reveal their characteristic features in comparison with the parent compound TbNi₅. The electronic structure of TbNi₄Fe and TbNi₄Co was calculated within the LSDA + U method (local spin density approximation with Hubbard U-correction). Based on the calculated electronic structure results, the theoretical optical conductivity was calculated and used to interpret experimental conductivity in the range of interband optical absorption.     

Localized convective flows in a nonuniformly heated liquid layer

Within the class of exact solutions of the thermal-convection equations in the Oberbeck-Boussinesq approximation, which assumes a linear dependence of the temperature and the vertical velocity component on the height, a non-self-similar behavior of localized disturbances of a special type in a nonuniformly heated liquid layer is studied. It is shown that in an unstably stratified medium these disturbances can evolve to isothermal vortex structures of Burgers type. In the conditions of stable stratification or uniform heating of the layer, the disturbances considered tend to the state of rest in an oscillating or monotonic manner. New solutions describing self-similar convective vortices are found.     

Electronic structure and optical properties of TbNi5−xCux

In this paper we present theoretical investigation of optical conductivity for intermetallic TbNi_5−xCu_x series. Within the framework of LSDA+U calculations, electronic structure for x=0, 1, 2 is calculated and additionally optical conductivity is obtained. Disorder effects of Cu for Ni substitution on a level of LSDA+U densities of states (DOS) are taken into account via averaging over all possible Cu ion positions in the unit cell for given doping level x. Gradual smoothing of optical conductivity structure at 2 eV together with simultaneous intensity growth at 4 eV corresponds to increase of Cu and decrease of Ni content.     

Bose—Einstein Condensation and Spin Superfluidity of Magnons in a Perpendicularly Magnetized Yttrium Iron Garnet Film

JETP Letters - The formation of a Bose—Einstein condensate of magnons in a perpendicularly magnetized iron yttrium garnet film under radio-frequency pumping in a stripline has been studied...     

Electronic Structure of the DyFe2Si2 Compound: Energy Band Calculations and Optical Studies

Physics of the Solid State - The electronic structure and the optical properties of the DyFe2Si2 compound have been studied. The calculations of the energy band spectrum taking into account the...     

Key structures in the synthesis of steroid antitumor agents. Methods for upbuilding the 17β-pregnane side chain of 3-methoxy-19-norpregna-1,3,5(10)-trien-20-ones with and without an additional 16α,17α-carbocycle

Russian Chemical Bulletin - Methods for extending the side chain of 20-oxopregnanes were summarized. The possibilities of alkylation of 3-methoxy-19-norpregna-1,3,5(10)-trien-20-one and its...