  Monte Carlo simulations have been performed to determine the excess energy
and the equation of state of fcc solids with Sutherland potentials for wide
ranges of temperatures, densities and effective potential ranges. The same
quantities have been determined within a perturbative scheme by means of two
procedures: i) Monte Carlo simulations performed on the reference hard-sphere
system and ii) second order Barker-Henderson perturbation theory. The aim was
twofold: on the one hand, to test the capability of the 'exact' MC-perturbation
theory of reproducing the direct MC simulations and, on the other hand, the
reliability of the Barker-Henderson perturbation theory, as compared with
direct MC simulations and MC-perturbation theory, to determine the
thermodynamic properties of these solids depending on temperature, density and
potential range. We have found that the simulation data for the excess energy
obtained from the two procedures are in close agreement with each other. For
the equation of state, the results from the MC-perturbation procedure also
agree well with direct MC simulations except for very low temperatures and
extremely short-ranged potentials. Regarding the Barker-Henderson perturbation
theory, we have found that, surprisingly, the first-order approximation is in
closer agreement with simulations than the second-order one.
