Perturbation theory for dipolar hard spheres

Grand partition function methods are used to generate formal perturbation theory expressions systematically through fifth order for the Helmholtz free energy (A) and through third order for the angle‐averaged two‐body radial distribution function of a system of hard spheres perturbed by embedded electric dipoles. Integrating as required over all dipole orientations causes most terms in these expressions to vanish such that numerical evaluation for the first time of the fourth‐order contribution to A appears to be feasible using the Monte Carlo method. This work is in progress. Copyright © 1982 John Wiley & Sons, Inc.