Nearly exact Green's functions for valence electrons in simple metals: Photoemission bandwidths and mean free paths

Abstract

We present a nearly exact solution to a Dyson equation for Green's functions of valence electrons in simple metals; the predicted quasiparticle properties agree well with known accurate results. A relaxation-time argument is given which leads to a nonequilibrium Green's function for an interpretation of the band structures measured in photoemission experiments. Calculations including the core-electron effects excellently account for the experimental data on bandwidths and mean free paths.