A semiempirical study of the electronic structure of calcium

Abstract

Results of calculations based on the KKR method, using a k dependent potential, are presented for Ca. A sufficiently large overlap of the first and second bands, at normal pressure, can be obtained by means of suitable parametrization of KKR method phase shifts. These are compared with those given by Gaspar like potential, having varying amounts of exchange energy. An l dependent Gaspar like potential is used to calculate normal pressure Fermi surface, and symmetry point eigenvalues. The widths of occupied and unoccupied d like states of 0.35 eV and 7.51 eV agree well with photoemission measurements. Calculations of effect of pressure indicate that Ca changes from metal to semimetal at compressed to normal volume ratio is 0.708, the experimental value being 0.67.