Application of hard sphere perturbation theory to a high-temperature binary mixture

We calculate the thermodynamics of a high-temperature binary mixture (kT/ɛ>50) using a WCA fluid perturbation theory and hard sphere reference system. The problems of the softness of the repulsive core and the nonadditivity of the hard sphere diameters can be successfully circumvented by using appropriate separations between the reference and the perturbation potentials, as shown by comparing the results with Monte Carlo simulations.