Abstract:

Molecular interactions in the heavy rare gases are studied by use of the Kihara core-model intermolecular potential. From second virial and viscosity coefficient data a gas-phase pair-potential function is constructed. This is applied to the calculation of the cohesive energy and lattice constant of solid argon, krypton and xenon. Zero-point energy effect and non-additivity of the pair potential are considered. Three-body effect is evaluated using Kihara's theory of dispersion forces. Similar calculations have also been made using a Lennard-Jones potential. Both the second virial coefficient data and the solid state properties are significantly better described by the new potential. Stability of the solid structures are correctly predicted for krypton and xenon. Results for viscosity are not, as yet, conclusive. Applying a simple relationship previously derived, the Kihara potential used here is still a two independent parameter potential function. The value of the coefficient of London forces is calculated from the new potential parameters.