An Isotropic Empirical Intermolecular Potential for Solid H ₂ and D ₂ : A Classical Molecular Calculation

Abstract

We develop an isotropic empirical potential for molecular hydrogen (H2) and deuterium (D2) by fitting to solidstate data, which is appropriate for classical molecular dynamics (CMD) approach. Based on the prior isotropic intermolecular potential used in self-consistent phonon approximation, a zero-point energy term and an embedded energy term are introduced to describe the H2–H2 and D2–D2 interactions in CMD simulations. The structure, cohesive energy and elastic properties of solid H2 (D2) are used as the fitting database. The present method is tested by calculating the melting point of solid H2, and the pressure and bulk elastic modulus as a function of volume. The developed potentials well reproduce many properties of solid H2 and D2.