Momentum Distribution and Pair Correlation of the Electron Gas at Metallic Densities

Abstract

The momentum-distribution and pair-correlation functions of the electron gas at metallic densities are calculated by means of an expression of the ground-state energy derived in a previous paper. Numerical studies of the momentum distribution show that even at metallic densities most of the electrons are still inside the Fermi sphere and that the Fermi surface persists. The effect of the exchange processes at metallic densities is found to pull the electrons back inside the Fermi sphere and to increase the discontinuity at the Fermi surface, which is the opposite effect to that at high density. The behavior of the pair-correlation functions indicates that at short distances the present results overestimate the correlation of antiparallel spins but underestimate that of parallel spins. On the whole, there is considerable improvement over the corresponding results in the random-phase approximation.