Vacancy formation energies and Faber's formula

Abstract

A formula due to Faber for the energies of formation of vacancies in metals is investigated from the general theoretical and numerical viewpoints. It is shown that the effective interatomic potential involved is of larger amplitude and longer range than that obtained by pseudopotential theory. Numerical success can be expected for monovalent and divalent metals. For higher valence cases it seems that non local electron-ion potentials or pseudopotential theory beyond second order (or both effects) must necessarily enter a successful formulation.