Anharmonic Parameters of Vibrationally Excited Molecules

An algebraic method of perturbation theory for eigenvalues and eigenvectors is used to examine the intramolecular parameters of excited vibrational states. Based on this method, formulas for higher-order coefficients of the matrix of vibrational modes, changes in the Cartesian coordinates of vibrating atoms, and anharmonic elements of the tensor of inertia moment are derived.     

Algebraic Method of Studying Excited Vibrational Transitions

The algebraic method of perturbation theory is used to solve problems in molecular spectroscopy. Formulas for the shifts in the band centers, changes of the form factors of excited vibrational transitions, and changes of the components of the kinematic interaction matrix are derived by this method for the nth order of perturbation theory.     

Modeling of High-Order Overtone Molecular Vibrations

A mathematical model of high-order overtone molecular vibrations based on the modified equation of normal vibrations and operation of direct matrix product is suggested. An algorithm for numerical solving a direct spectroscopic problem for overtones has been constructed together with a computational program. Calculations by this program within the framework of the CNDO/2 quantum-chemical method and method of numerical differentiation with cubic splines are used to carry out a computer experiment on calculation of the high-order overtone vibration intensities for the carbon tetrafluoride molecule and its isotope.__________Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 48–52, March, 2005.     

Thermal conductivity of the single-crystal monoisotopic 29Si in the temperature range 2.4–410 K

Physics of the Solid State - The temperature dependence of the thermal conductivity κ(T) of single-crystal silicon highly enriched in 29Si (99.919%) isotope has been measured in the...     

Coefficients of Kinematic Interaction between Excited Vibrational States

Within the framework of an algebraic perturbation method for eigenvalues and eigenvectors and using a theory of projectors, the structure parameters of excited molecular vibrations are investigated. To do this, formulas for the higherorder elements of the vibrationform tensor have been obtained on the basis of which and in conformity with the order of the perturbation theory the changes in the intramolecular dynamic parameters and in the coefficients of the kinematic interaction between the excited vibrational states are determined.     

Behavior of phosphorus impurities during Czochralski growth of high‐purity germanium single crystals

The effect of evaporation of phosphorus impurities from the melt is investigated as well as the contaminating effect of quartz glass crucibles on residual content and distribution of this impurities by length of high‐purity germanium single crystals. The residual content of phosphorus impurities is mainly influenced by the contaminating effect of crucible material and its distribution by length of crystals is described by the model accounting for the impurities income from crucible material. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

IR absorption and Raman spectra of single crystals of stable germanium isotopes

The Raman and IR absorption spectra of single crystals of germanium isotopes ⁷²Ge, ⁷³Ge, ⁷⁴Ge, and ⁷⁶Ge in the region of phonon absorption and interband electronic transitions are studied at room temperature. The dependence of the Raman peak position on the atomic mass has the form ν ~ M^–1/2. The shifts of the phonon absorption peaks of individual isotopes with respect to germanium of natural isotopic composition ^natGe are determined. With increasing average atomic mass of germanium, these peaks shift to longer wavelengths. In the region of interband electronic transitions, the intrinsic absorption edge of ⁷⁶Ge is observed to shift by 1 meV to higher energies with respect to Ge of natural isotopic composition. For isotopes with atomic masses close to that of natural germanium (⁷²Ge,⁷³Ge, ⁷⁴Ge), we found no significant difference in the band gap width at room temperature.     

Algebraic approach to the study of excited vibrational states

The algebraic method of perturbation theory for eigenvalues and eigenvectors is used for the theoretical study of molecular parameters of excited vibrational states. Within the framework of this method, formulas for higher-order elements of the vibration form tensors are obtained. They can be used for the study of changes in intramolecular parameters of vibrations and the anharmonic coefficients of kinematic interaction.     

Overtone vibrations of molecules

A vibrational equation for overtones is derived by applying the direct multiplication of matrices in the framework of the molecular vibration theory. The relationships determining the characteristics of the overtone vibration mode and expressions describing the changes in the structural and geometric molecular parameters are obtained by solving the deduced equation. The electro-optical parameters of the overtones 2ν_s, 3ν_s, 4ν_s, and 5ν_s(s=3, 4) of a methane molecule are calculated from the deduced relationships using the semiempirical quantum-mechanical CNDO/2 method and numerical differentiation with cubic spline functions.