A thermotropic nematic of slightly non-spherical molecules: generalized van der Waals theory

A simple generalization is given of the Maier-Saupe model of thermotropic l iquid crystals to the case of slightly non-spherical particles. This allows the inclusion of multipolar forces at the mean-field level. Additionally, it is shown that increasing the (small) molecular elongation may actually d estabilize the nematic phase. Within the present scheme, the roles of (shor t range) overlap and (long range) dispersion forces in determining phase be haviour can be assessed separately.