Ellipsoid contact potential: Theory and relation to overlap potentials

Abstract
We propose and analyze the properties of a simple, computationally efficient pair potential for nonpolar molecules based on the contact function for ellipsoidal cores. We discuss the relation of this potential to the Gaussian overlap potential and show that the present potential gives the correct extension of the ideas of the Gaussian overlap potential to mixtures. We show that this potential obeys a form of the principle of corresponding states and derive an expression for the second virial coefficient. As this potential has an incorrect symmetry at large separations, we derive another contact potential that behaves isotropically at infinite separation. Unfortunately, this potential does not have the good computational features of the one investigated here.