Electronic structure of alkaline metal hydrides according to MO LCAO-SCF-CNDO cluster calculations

Abstract

This paper presents the results of a quantum chemical study of compounds MH (M = Li, Na, K, Rb, and Cs) in a cluster approximation. The calculations were performed by the MO LCAO-SCF-CNDO method (special variation which proved to be effective for studying model systems of high-temperature superconductors). The calculation reproduces the expected electron density distribution on the hydrogen and metal atoms in the hydrides as well as the energy characteristics: M-H and M-M bond energ.es and the binding energies of compounds. The latter qualitatively correlate with the bond energies in the series of compounds LiH-CsH. The calculated Fermi energies and forbidden gaps at the Fermi level suggest that in the series being investigated a perfect crystal of lithium hydride will have the highest electric resistance. It is established that the quantum chemical characteristics of the electronic structure of MH change nonmonotonically from Li to Cs.