No abstract

A temperature-dependent (preaveraged) potential independent of orientation, which is thermodynamically equivalent to an orientation-dependent two-and three-body potential, is developed. The influence on the preaveraged potential of angle-dependent pair interactions (which arise from permanent electric-multipole moments, induced dipole moments, anisotropic dispersion and overlap forces), of three-body non-additive interactions (which arise from dispersion and classical electric-induction interactions between asymmetric molecules) is considered. This preaveraged potential is used to devise a simple perturbation scheme for the calculation of the thermodynamic properties in terms of the properties of a hard-sphere fluid. The calculated thermodynamic properties (configurational energy, entropy and pressure) for nitrogen and methane are in very good agreement with the experimental data.

No abstract

No abstract

No abstract