Computer simulation of nematic reentrance in a simple molecular model.

We report a computer simulation study of a system of parallel hard ellipsoids with attractive interactions represented by a spherically symmetric square well of range lamba. For suitable values of the results are consistent with the sequence of phases nematic (N), smectic-A (SmA), reentrant nematic (N(re)), and crystal (Cr) under pressure. Both the N-SmA and the SmA-N(re) transitions are found to be first order or continuous depending on temperature. Moreover, we show that a generalized van der Waals-type theory provides a qualitative description of the observed phase behavior.