4fN-15d energy levels of lanthanides: aquasi-angular-momentum approach and its application to Cs2NaYF6:Er3+

<正>The spin-orbit interaction of the 5d electron needs to be taken into account to give the proper energy structure for the 4f^N-15d configuration of heavy lanthanide ions occupying a site with ligands forming an octahedron.This paper derives theoretical results for the energy structure by treating the t₂ orbitals as quasi p orbitals and then using angular-momentum coupling techniques.An analytic expression for the electric dipole absorption line strengths between 4f^N multiplets and 4f^N-15d states is given in terms of various angular-momentum quantum numbers and re-coupling coefficients.The result is then applied to interpret the excitation spectrum of Cs₂NaYF₆:Er³⁺.The high-spin and low-spin states of Cs₂NaYF₆:Er³⁺ are discussed in terms of the wavefunctions obtained by using the developed theoretical model.     

Moutard transformation and its application to some physical problems. I. The case of two independent variables

We propose a general scheme of application of the Moutard transformation to second-order partial differential equations with two independent variables. A realization of this scheme is given for the nonstationary Schrödinger equation and Fokker–Planck equation as well for the wave and Helmholtz equations. Bibliography: 18 titles.     

The thermodynamic properties of solutions of L-ascorbic acid in dimethyl sulfoxide and water-dimethyl sulfoxide mixtures

Solutions of L-ascorbic acid (AA) in dimethyl sulfoxide (DMSO) and DMSO-water mixtures were studied by the densitometry, surface tension, and calorimetry methods. The apparent and partial molar volumes of AA in solutions at 298.15 K were calculated. Surface tension insignificantly increased as the concentration of AA in DMSO grew. The enthalpies of solution of AA in the solvents and the enthalpies of transfer of AA from water into DMSO and DMSO-water mixed solvents were calculated. The results obtained were explained by the existence of H-bonds between AA and DMSO molecules.     

Bisindoles 34. Preparation and reactions of dehydrazides of the benzo[e]pyrrolo[3,8-g]-indole and indolo[4,5-e]indole series

Summary 2, 9 -Di (carbohydrazide)-1 H, IOH-benzo[elpyrrolo[3, 2-g]indole and 2, 9-di (carbohydrazide)-3H, 8H-indolo[4, 5-e]indole have been prepared. Nitrosation of the dihydrazides has been effected. The aryl azides do not undergo the curtius rearrangment.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1048-1051, August, 1994.Communication 33, see [1].     

Calculation of aerosol particle trajectories in the velocity hodograph plane

A method is proposed for calculating the trajectories of aerosol particles. The method is based on transforming the equations of particle motion to the variables of the hodograph plane of the carrier phase velocity. This greatly samplifies the integration of the equations. As an example, the problem of an aerosol jet injected from a slit nozzle and spreading over a plane is solved.Kzzan'. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 3, pp. 129-134, May-June, 1994.     

Structure of artabin

Summary FromArtemisia absinthium L. a new sesquiterpene lactone of the germacrane type — artabin — has been isolated. Structure I is proposed for it.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR. Translated from Khimiya Prirodnykh Soedineii, No. 6, pp. 691–694, November–December, 1970.     

Promotion of nickel catalysts for the steam reforming of methane

The influence of additives (Cu, Fe and Al₂O₃) on the textural and catalytic properties of nickel in steam reforming of methane is described. The effects of structural promoting by Al₂O₃ and of electronic promoting by copper are reported. The rate of steam reforming of methane was measured in a gradientless reactor at atmospheric pressure.

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(Cu, Fe Al₂O₃) . Al₂O₃ . .

     

Conformational analysis of 5,5-bis(halomethyl)-1,3-dioxanes

Investigation of stationary points on the potential energy surface of a number of 5,5-bis(halomethyl)-1,3-dioxanes using DFT-approximation of PBE/3ζ revealed the only path of chair form interconversion proceeding through an intermediate minimum corresponding to a 2,5-twist-conformer.     

Synthesis and biological activity of some gossypol derivatives

Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 44–49, January–February, 1995. Original article submitted October 17, 1994.