Interatomic potential from density functional theory with application to metallic hydrogen

Abstract

We propose an extension of the usual perturbative approach for calculating interatomic potentials in simple metals which is based on the density functional formalism. The procedure uses nonlinear self-consistent calculations of the displaced electron charge density distribution Δnλ(r) about an external charge λZ immersed in an electron gas, with λ ranging from 0 to 1. The interatomic potential is then obtained by an integration over λ of a function involving Δnλ(r). Results are obtained for the case of two protons (Z = 1) and applied to metallic hydrogen. The resulting phonons and superconducting transition temperatures are found not to differ much from those obtained in a recent calculation using a different approach.