Density-dependent potentials for simulations

Abstract

The authors have obtained a simple analytic pair potential and volume potential for simulations of simple metals in which the density dependence of the parameters is given explicitly. The potentials are based on a first-principles nonlocal pseudopotential theory with a correction term in the volume potential to allow for the effects of the density dependence of terms in the total energy beyond second order in perturbation theory. This correction term gives the pressure required to obtain the measured equilibrium lattice constant. In this paper the authors present a potential for Li and show that it gives the FCC structure at low temperatures, and gives good agreement with measured phonon dispersion curves and elastic constants.