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Atomic Distance (atomic + distance)
Selected AbstractsTotal cluster energy calculation of lithium ion conductors by the DV-X, methodINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 12 2009Y. Kowada Abstract Recently, several programs for the total cluster energy calculation have been developed in the DV-X, method. In this study, we have calculated and compared total cluster energies of several diatomic molecules and model clusters of ionic conductors. The total cluster energies of diatomic molecules are minimum near the equilibrium atomic distance of each molecule though the absolute value of the total cluster energy was slightly different from each other. In the case of the model cluster of the Li3N crystal, which is one of the typical Li ion conductors, we have obtained the energy change as a function of the site during the movement of a Li ion. The energy change with the movement of the Li ion along the conduction path was considerably smaller than along other paths, consistent with the results by the band calculation and experiments. The total cluster energy calculation method was useful enough for the discussion of the cluster energy. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009 [source] Inhomogeneous surface electronic properties and charge ordering in epitaxial Fe3O4 films on MgO(001)PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 12 2007A. Subagyo Abstract We report scanning tunneling microscopy (STM) study of surface electronic properties and charge ordering of epitaxially grown magnetite, Fe3O4, (001) films exhibiting high density of antiphase domain boundaries (APBs). STM measurements using a W tip reveal surface termination at B-sites. Fe ions with a 0.3 nm periodicity, i.e., a single atomic distance are observed. Current imaging tunneling spectroscopy reveals the alternation of two kinds of current peaks with a 0.6 nm periodicty indicating the presence of charge ordering consisted of Fe dimers with different charge states. STM measurements using a magnetic Ni tip provide higher contrast of the charge ordering. The APBs can modify the charge ordering as ordered and disordered areas are observed on adjacent domains separated by an APB. These strongly indicate that APBs can induce inhomogeneous properties on the surface of Fe3O4(001) films. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Lattice dynamic investigation of the Raman and infrared wavenumbers of orthorhombic R2BaCuO5 (R = Y, Ho, Gd) oxidesJOURNAL OF RAMAN SPECTROSCOPY, Issue 1 2005H. C. Gupta Abstract A short-range force constant model was applied for the first time to investigate the Raman and infrared wavenumbers in R2BaCuO5 (R = Y, Ho, Gd) oxides in their orthorhombic phase of space group Pnma. Calculations of zone center phonons were made with 17 stretching and four bending force constants. The force constants were evaluated using the electronegativities and the atomic distances. The calculated values of Raman wavenumbers are in reasonable agreement with the available observed values. The infrared wavenumbers were assigned for the first time. Copyright © 2004 John Wiley & Sons, Ltd. [source] Atomvolumen, Packungsdichte der Atome und chemische Bindung in nichtmetallischen ElementenACTA CRYSTALLOGRAPHICA SECTION B, Issue 4 2007M. Trömel The atomic volume of crystalline elements is largely determined by the packing density of atoms in the respective modification. The determination of packing density is improved by assuming that the atomic distances depend on bond valences according to Pauling's equation. With the additional assumption of equal valence in different modifications, the experimental atomic volume of an element in any given structure is reduced to its volume in close-packed structures, e.g. f.c.c. The ratio of this reduced atomic volume and the experimental atomic volume is a measure of packing density. Reduced atomic volumes of C, Si, Ge, P, As, S and Se, as calculated from different modifications, correspond in most cases to within less than ±1% for each element, even if calculated from extremely different structures like diamond and buckminsterfullerene in the case of carbon, or from numerous modifications of sulfur with annular molecules of different sizes. Exceptions (graphite, white phosphorus, tin and selenium) indicate deviating valences. [source] | ||||||||||