The freezing of soft spheres from a simple hard-sphere perturbation theory

Abstract

It is shown that a simple perturbation expansion around the free energy of a (BCC/FCC) hard-sphere crystal leads to accurate predictions for the (BCC/FCC) freezing of soft spheres interacting via the inverse-power potential, V(r)= epsilon ( sigma /r)n, for all values of n including the extreme case of the one-component plasma (n=1). In particular, the authors find that for 1<or=n<or=6 there is both a fluid-BCC and BCC-FCC transition whereas for n>6 the BCC phase is unstable and only the fluid-FCC transition survives, in agreement with the computer simulations.