ELECTRONIC ENERGY STRUCTURE OF MBiS2 (M = Li, Na, K) CALCULATED WITH ALLOWANCE FOR THE DIFFERENCE BETWEEN THE M-S and Bi-S bond lengths
B. V. Gabrel'yan, A. A. Lavrentiev, I. Y. Nikiforov, V. V. Sobolev
Keywords: electronic structure, sulfides, density of electronic states, X-ray spectra
Pages: 821-826
Abstract
The modified augmented plane wave method (WIEN2k program) was used to study the electronic energy structure and calculate the SK-absorption spectra of LiBiS2, NaBiS2, and KBiS2. The crystal structures of the compounds were modeled using symmetric structures, in which each sulfur atom was surrounded by three alkali metal atoms and three bismuth atoms in such a way that the alkali metal-sulfur and bismuth-sulfur bond length differed. This difference between bond lengths was calculated from the sum of the ionic radii of the components of compounds and by the geometry optimization of the crystal lattice. The two variants of calculation allowed us to check the applicability of Pauling's idea about preservation of the bond lengths of elements in compounds for modeling the crystal structures of LiBiS2, NaBiS2, and KBiS2. The SK absorption spectra and optically forbidden bands were calculated.
|
