Electronic structure and EPR spectra of V4+ in TiO2, SnO2, and GeO2

Autor: F. M. Michel-Calendini, G. Fichelle
Rok vydání: 1975
Předmět:
Zdroj: physica status solidi (b). 69:607-618
ISSN: 1521-3951
0370-1972
DOI: 10.1002/pssb.2220690236
Popis: The energy levels of V4+ in a VO68− complex of D2h symmetry are computed according to an extended LCAO method with non-orthogonal orbitals. The substitutional impurity is trapped in TiO2, GeO2, and SnO2 lattices. The results are compared with previous calculations on these structures. The interband transitions at the centre of the Brillouin zone are related to optical data with a good approximation. A first tentative is made to explain the X-ray spectra of TiO2 according to the molecular diagram. The g-factors and the hyperfine structure constants are computed and the covalency of molecular orbitals is taken into account. The following results are obtained for gx, gy, and gz:1.917, 1.893, 1.966 for V4+(TiO2), 1.937, 1.869, 1.953 for V4+ (SnO2) and 1.928, 1.911, 1.970 for V4+ (GeO2). The corresponding values of Ax, Ay, and Az in 10−4 cm−1 units are: 35, 40, and 141 for V4+(TiO2), 27, 40, and 148 for V4+(SnO2), and 41, 43, and 128 for V4+ (GeO2). A comparison is made with previous works using the point charge model. The LCAO calculations give results in agreement with the values deduced from EPR experiments.
Databáze: OpenAIRE
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