Correlation Contribution to the Surface Energy of Metals

Abstract
We have derived a formal expression for the free energy of an electron gas confined in a slab geometry (within the Random Phase Approximation). The result is expressed in terms of the bulk and surface dielectric functions. The structure of the perturbation theory (in e 2) of the surface energy terms is carried out in the high density limit. The correlation part of the surface energy has been numerically evaluated in an approximate scheme. The result is found to be a factor of five larger than the Lang and Kohn correlation energy.