Structural Expansion for the Ground-State Energy of Simple Metals. II

Open Access
Publisher Website
Google Scholar
Abstract
A self-consistent treatment is given for the Green's function which determines the structure-dependent part of the ground-state energy for simple metals. An expansion in the resulting screened interactions is given exactly up to fourth order. In addition to the previously examined one-electron terms (I), which are the most important ones, the present paper treats the next important terms which may be related to the first-order effect of the exchange energy due to inhomogeneous charge distribution. In fourth order of the expansion, the mentioned term shows the same singularity as the third-order one-electron term, Brovman and Kagan's singularity. It is proved that the Hartree-Fock result exaggerates the first-order exchange effect, most strikingly in the close vicinity of the singular point. Effect of the dynamical shielding on the considered term is also studied, particularly in the third-order term of the expansion.