Third‐order contribution to the energy and the elastic constants of simple metals

Abstract

Abstract The energy of a metal is usually calculated by second‐order perturbation theory in the pseudopotential. It is, however, also possible to calculate the third‐order contribution. This contribution is calculated to the energy and the elastic constants of Al and Na using two different types of local model potentials in order to see how the choice of the potential will influence the magnitude of the third‐order contributions.