Solid-fluid coexistence for inverse-power potentials.

We report Monte Carlo studies of solid-fluid coexistence for the soft-sphere potential: @(r) = e(cr/r)" Applying a recently developed integration method that proceeds along a coexistence line, we determined coexistence for essentially a continuum of softness s —= l/n from s = 0 (hard spheres) to ca. s = 0.25. For s ~ 0.16, we estimate that fcc is the stable crystal, and that bcc is stable for softer potentials; however, this result is not conclusive. We find substantial disagreement with early coexistence data for n = 12, 9, 6; and 4, while confirming more recent studies for n = 12 and 6.