
%0 Journal Article
%A Johnson, CHJ 
%A Spurling, TH 
%T Non-additivity of intermolecular forces: effects on the fourth virial coefficient
%J Australian Journal of Chemistry
%D 1974/02/01
%V 27
%N 2
%P 241-247
%K 
%R https://doi.org/10.1071/CH9740241
%U https://www.publish.csiro.au/paper/CH9740241 
%X In this paper we give the results of computing the effect of non-additivity of long range forces on the fourth virial coefficient of a Lennard-Jones 12-6 gas. We have considered only dipolar effects but have included all terms up to the fourth order of perturbation theory. We have also calculated the effect of the fourth-order triple-dipole term on the third virial coefficient. For the fourth virial coefficient we find that the dispersion non-additivity, while being positive at low reduced temperatures, goes through a negative minimum at a reduced temperature of about 1.25 before becoming small and positive at high temperatures. This is in contradistinction to the behaviour of the third virial co-efficient where the dispersion non-additivity is always positive. 
