Green’s-function calculation of electron screening in a plasma

Abstract

Extensions to the finite temperature Green's-function method for the calculation of equilibrium densities within the Kohn-Sham formulation of density functional theory are presented. In particular, an expression for the density in terms of single-particle Green's-function differences summed over all Matsubara poles is utilized. Numerical methods for the evaluation of this infinite sum are given. This formulation automatically includes discrete as well as continuum states, is valid for finite temperatures, and is especially well suited for high temperatures. Techniques are also presented for the calculation of single-particle Green's functions for spherically symmetric systems and arbitrary complex energies. The usefulness of these methods is demonstrated by their application to the problem of electron screening of nuclei in a plasma. Direct comparison is made with previous finite temperature, Kohn-Sham, wave function type calculations for protons and for neon nuclei in an electron gas.