Energy Bands and the Optical Properties of LiCl

Abstract

Using a recently developed local-orbital theory of the author's, the ground-state eigenfunctions of the LiCl crystal in the Hartree-Fock approximation have been obtained. Using these functions to form the crystal charge density, the one-electron energy bands have been computed in essentially the Hartree-Fock approximation using the mixed-basis technique. Various levels of approximation within the local-orbital approximation are investigated. Polarization corrections to the energy bands are included by the method of Fowler. Finally, using tight-binding interpolation for the valence levels and empirical pseudo-potentials for the conduction bands, the density of states for the valence and conduction states are obtained, and a joint density of states is computed. Extensive experimental comparisons are made. The principal results are the following: (1) The valence bands are very wide ($3p$ band is about 8 eV wide). (2) The soft x-ray spectrum can be interpreted in terms of the band structure. (3) Polarization corrections are significant.