Computed transport coefficients for van der Waals systems via realistic interactions

Abstract

Approximate methods are employed to calculate generalized collision integrals for gas phase rotationally inelastic processes in mixtures of N₂ with He, Ne and Ar. A detailed comparison is performed between theoretical diffusion and viscosity coefficients and the available measurements at various temperatures. Because of the relatively weak interactions involved, by using several existing potential energy surfaces one can specifically relate the behaviour of the transport coefficients to the ‘shape’ and ‘size’ of the averaged, effective interactions which are probed by these properties. For each of the systems examined the most reliable potential energy surface is therefore selected and recommended for calculations.