HARD ELLIPSOIDS OF REVOLUTION WITH SQUARE WELLS - A COMPARISON BETWEEN COMPUTER-SIMULATION AND THEORY IN THE LIQUID VAPOR REGION

We present preliminary computer simulation results on an anisotropic model of molecular fluids. The model can be regarded as a generalization of the square-well model to the case in which the hard core is non-spherical. In this work we restrict ourselves to uniaxial hard ellipsoids of revolution. By using Monte Carlo in the Gibbs ensemble we calculate the liquid-vapour coexistence curves for several elongations. The corresponding results are then compared with the predictions of a van der Waals theory. It is found that the theoretical predictions underestimate the location of the coexistence densities and critical points; the discrepancies are more severe for oblate molecules than for prolate ones.