Calculation of spectral and Rosseland paths in a plasma with multiply charged ions based on a statistical approach

The semiclassical approach to determine the Fourier components of the electron dipole moment disregarding polarization (noninteracting electron model) is used for analyzing ion oscillator strengths and determining the radiation properties of plasmas consisting of multiply charged ions of heavy elements. The oscillator strength distribution df/d?? (proportional to the photoabsorption cross section) is calculated as a function of the degree of ionization and self-similar frequency ?? = ??/Z. It is found that for low degrees of ionization, function df/d?? for an ion is close to function df/d?? for a neutral atom; upon an increase in the degree of ionization, regions are formed in which df/d?? = 0 (transparency windows) and the photoabsorption cross section for high degrees of ionization differs from zero only in small frequency ranges. The resultant distribution of the ion oscillator strengths is used for calculating the polarizability of ions as a function of frequency and the cross section of radiation scattering on ions. For a gold plasma, the absorbance and opacity (both spectral and averaged according to Rosseland and Planck) are calculated. The results of computing the paths and absorption coefficients coincide in order of magnitude with the available data. The effect of scattering on the Rosseland path is estimated.     

Optical properties of iron alloys with heavy rare-earth elements

Spectral-ellipsometric measurements by the Beatty method were made in the region from 1 eV to 4 eV at temperatures of 100, 293, and 700 K to determine the relation between the distinctive features of the optical absorption spectrum and the principal parameters of the electron energy spectrum in iron alloys with rare-earth elements. The fundamental bands of interband optical absorption of Fe₂-R alloys (R=Gd, Ho, Er) in the region 2.8–3.1 eV are formed by indirect transitions from d-like states, which are genetically bound to 3d–5d electrons of the transition metal and the rare-earth metal, in a state above the Fermi level.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 64–67, December, 1988.We thank our senior research colleague V. A. Domyshev for supplying the samples and carrying out the x-ray structure analysis.     

Steroids of the spirostan and furostan series from plants of the genus Allium. XXI. Structure of alliospiroside a and alliofuroside a from Allium cepa

Two new steroid glycosides have been isolated from the generative organs (pericarps and peduncles) ofAllium cepa L.: alliospiroside A and alliofuroside A. According to chemical transformations and spectral characteristics, alliospiroside A has the structure of (25S)-spirost-5-ene-1,3-diol 1-O-[O--L-rhamnopyranosyl-(1 2)--L-arabinopyranoside]. The structure of (25S)-furost-5-ene-1,3,22,26-tetraol 20-O--D-glucopyranoside 1-O-[O--L-rhamnopyranosyl-(1 2)--L-arabinopyranoside] has been established for alliofuroside A.Institute of the Chemistry of Plant Substances of the Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 188–196, March–April, 1986.     

Studies of molybdenum in Mo?Ti oxide catalysts

ESR studies indicate that in Mo–Ti oxide catalysts prepared via the addition of ammonium paramolybdate to pasted titanium hydroxide, Mo⁵⁺ ions are observed in three states: in heteropoly blue, disperse MoO₃ and a solid substitutional solution in TiO₂.

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, , - , - Mo⁵⁺— , MoO₃ TiO₂.

     

Magnetooptical properties of Co-SiO<Subscript>2</Subscript> granular films

The structural, optical, and magnetooptical properties of Co-SiO₂ granular films are studied. It is found that the magnetooptical response is considerably enhanced in samples with a metal component concentration close to the percolation threshold. The Co nanogranules formed in the SiO₂ matrix exhibit ferromagnetic properties and are ordered into the fcc structure, which is confirmed by magnetooptical investigations. The magnetooptical properties of nanocomposites are simulated in the effective-medium approximation. It is shown that the singularities found in the magnetooptical spectra are related to the excitation of plasmon resonances in granular films.