Saturated Liquid Properties from the Mie(n, 6) Potential and the Barker-Henderson Perturbation Theory

The perturbation theory of Barker and Henderson [J. Chem. Phys. 47, 4714 (1967)] has been used to test various Mie(n, 6) intermolecular pair potentials for their ability to predict liquid properties. The properties studied were the residual energies, entropies, and heat capacities in four saturated liquids: argon, nitrogen, methane, and perfluoromethane. The potential energy function parameters (ε/k, σ, n) used in most cases are those obtained by Klein [Natl. Bur. Std. (U.S.) AECD-TR-67–67] from second virial coefficient data. It is shown that it is possible to obtain a considerable improvement in predicted liquid properties if the parameter n is allowed to vary from the value 12 usually assigned to this parameter.