Search

The liquid-vapor phase diagram and surface tension for the Sutherland fluids with a variable range of interaction have been determined by canonical Monte Carlo simulations and compared with the augmented van der Waals analytic theory. The theory, based on a short-range Yukawa reference, performs well for medium-range models but its accuracy deteriorates with the shortening range due to deteriorating accuracy of the underlined analytic mean spherical approximation solution for the reference Yukawa potential. The simulation results are also analyzed from the point of the extended principle of corresponding states and it is shown that the surface tension and also, to a certain degree of accuracy, the vapor-liquid coexistence curve satisfy the principle.

A novel perturbation approach for the structure factor S(k) of the Lennard-Jones-type Yukawa fluid with z=1.8 is presented. An approach is based on a new reference system, that is, the short-range Yukawa model with z0>z=1.8. By choosing for the reference system the value z0=6, it is shown that (i) the proposed approach for S(k) performs much better than the traditional hard-sphere reference perturbation method does; (ii) the use of an approximate mean spherical (MSA) description of the reference structure factor provides the results for S(k) that are more accurate as those obtained from the direct MSA computations; and (iii) the results obtained for S(k) tend to reproduce “exact” simulation results when accurate simulation data for the reference system are used.