The Calculation of Corrections to the Random Phase Approximation for an Interacting Electron Gas in the Ground State

Abstract

<p> This work is concerned with the calculation by means of many-particle perturbation theory of the lowest order corrections to the Random Phase Approximation (RPA) description of an interacting electron gas in its ground state. Expressions in terms of the dynamically screened coulomb interaction are obtained for the electron proper self-energy, the electron momentum distribution function, and the screening function. Techniques, which reduce computational labour to a manageable level, are developed for the practical evaluation of the required corrections. The numerical results are not conclusive but they indicate that when all corrections of the same order (in the screened interaction) are included, the expansion converges sufficiently rapidly that the results are valid in the range of metallic densities.</p>