Comparison of Classical Monte Carlo Experiments with Improved Self-Consistent Phonon Theory: Thermodynamic Properties of Solid Xe

The improved self-consistent phonon theory (ISC) is compared with classical Monte Carlo experiments for a model approximating solid Xe. A Lennard-Jones (LJ) (12-6) nearest-neighbor (nn) potential is used to calculate the lattice constant, expansivity, Cᵥ, Cₚ, the bulk modulus, and the thermodynamic Gr\"uneisen parameter. The ISC is found to be only semiquantitative at high temperatures. By comparing the Monte Carlo results for high temperature and the ISC for low temperature with experiment we can see deficiencies in our simple nn model of the interatomic forces in solid Xe.