Different Types of Phase-Shift Pseudopotential with Application to the Alkali Metals and Copper

Abstract

The total pseudopotential in a metal can be expressed in many ways as a sum of atomic pseudopotentials. One way involves the usual "linear-screening" potential and another a "minimum-perturbation" potential. These different types of pseudopotential can be constructed by fitting experimental Fermi-surface data in terms of phase shifts within the formalism of the augmented-plane-wave method of band-structure calculation. An investigation is made of the effect of choosing different values of the "Fermi energy parameter" which defines the mean interstitial potential relative to the absolute Fermi level. Pseudopotential form factors calculated from the empirical phase shifts are presented for the alkali metals and copper.