SOLID TO SOLID ISOSTRUCTURAL TRANSITIONS - THE CASE OF ATTRACTIVE YUKAWA POTENTIALS

We present a density functional study of the expanded fcc to condensed-fcc transition of a system of hard spheres with an additional short-range attractive Yukawa potential. The approach rests on a separation of the interaction into a hard-sphere reference part, treated nonperturbatively by means of the modified weighted-density approximation, and a mean-field treatment of the attractive Yukawa tail, in analogy with earlier work on the short-range square-well potential. The method confirms the existence of an fcc-fcc isostructural transition terminating at a critical point, and yields results for the critical temperature that are in very good agreement with simulations.