Comparative study of the nematic phase-isotropic phase transition in systems of uniaxial hard cores

Abstract

We apply the smoothed density approximation to study the nematic phase-isotropic phase transition (N-I) for the following systems: hard ellipsoids of revolution (HE), hard spherocylinders (HSC), and cylinders (HC). We find that the transition is very sensitive to the shape of the hard core modelling a liquid crystal molecule. In the case of HC, the nematic phase can exist in the whole range of elongations x, while for HE and HSC the nematic density at the transition exceeds the close packing density in some range of x, around x = 1. Also the dependence on x of the nematic order parameter, Q, the density, Δη, and entropy, ΔS, jumps at N–I transition is completely different for HC in comparison to HE and HSC.