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The chemical bond overlap plasmon as a tool for quantifying covalency in solid state materials and its applications to spectroscopy

Authors

  • Renaldo T. Moura Jr.,

    1. Departamento de Química Fundamental, Universidade Federal de Pernambuco, 50740-540, Recife-PE, Brazil
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  • Oscar L. Malta,

    1. Departamento de Química Fundamental, Universidade Federal de Pernambuco, 50740-540, Recife-PE, Brazil
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  • Ricardo L. Longo

    Corresponding author
    1. Departamento de Química Fundamental, Universidade Federal de Pernambuco, 50740-540, Recife-PE, Brazil
    • Departamento de Química Fundamental, Universidade Federal de Pernambuco, 50740-540, Recife-PE, Brazil
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Abstract

The polarizability of the charge density in the overlap region of a chemical bond has already been correlated to its covalency in diatomic molecules and in lanthanide compounds. This concept has been successfully extended in the present contribution to alkali halide MX (M = Li, Na, K and X = F, Cl, Br) crystals. For more covalent compounds such as silicon, aluminum, and tin oxides the proposed treatment of the crystalline environment cannot be considered quantitative. However, for MX systems, good correlations between the chemical bond overlap polarizabilities and macroscopic properties such as molar polarizabilities and energy band gaps were established. In addition, the overlap region is regarded as a localized plasmon-like charge distribution (chemical bond overlap plasmon–CBOP), thus leading to absorption and Raman scattering processes by the overlap region, and electron energy-loss spectroscopy. The processes associated with CBOP excitations and energy-loss have been used to assign structures and shoulders present in spectra of MX crystals that have either not been assigned or ambiguously assigned as excitons or surface plasmons excitations. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010

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