Microscopic pair potentials and the physical properties of the condensed phase of parahydrogen

TL;DR

This study compares different pairwise potentials for simulating parahydrogen's condensed phases, finding that the recent ab initio potential aligns better with experimental data, especially in structural properties.

Contribution

It evaluates the effectiveness of various intermolecular potentials, highlighting the improved accuracy of the Patkowski et al. potential for condensed phase simulations.

Findings

Patkowski et al. potential yields better structural agreement with experiments.

It may overestimate the kinetic energy per molecule by up to 10%.

The potential is recommended for moderate pressure simulations.

Abstract

Equilibrium physical properties of the solid and liquid phases of parahydrogen, computed by first principle computer simulations, are compared for different choices of pairwise, spherically symmetric intermolecular potentials. The most recent ab initio potential [Patkowski et al., J. Chem. Phys., 2008, 129, 094304], which has a stiffer repulsive core than the commonly used Silvera-Goldman, yields results for structural quantities in better agreement with the most recent experimental measurements, while possibly overestimating the kinetic energy per molecule by as much as 10%. Altogether, the comparison between theory and the available experimental evidence suggests that the potential of Patkowski et al. may be a better choice for simulations of condensed phases of parahydrogen at moderate pressure.