Empirical Intermolecular Potential for Inert Gas Atoms

Abstract

Transport and thermodynamic calculations for gases at high temperature call for reliable interaction potentials at close approach. Potentials for the noble gases can be extrapolated approximately, yet with some reliability, from the empirical fit of properties in the ordinary range, using a screened Coulomb repulsion and a dispersion attraction reduced by a suitable factor at close approach. Parameters for this potential can be obtained approximately from the known parameters for the exp-six potential. The resulting empirical coefficient for the Coulomb term is found to be of the general order of magnitude given by the product of the nuclear charges. If the theoretical Coulomb repulsion is used, the screening exponent may alternatively be chosen on the basis of other empirical parameters.