Molecular dynamics simulation studies of a model system for liquid crystals consisting of rodlike molecules in NPT ensemble

Molecular dynamics simulation studies for thermotropic Liquid crystalline s ystems composed of rodlike molecules with 6 Lennard-Jones interaction sites were performed in NPT ensemble. Within the range of temperature studied, t he system exhibited isotropic and smectic phase. For the characterization o f the smectic phase, we examined the structure of the liquid crystalline ph ase via the radial distribution function, its longitudinal and transverse c omponents to the director, and other orientational correlation functions. I n the smectic A phase, our results showed a large anisotropy in translation al motion (i.e., D-perpendicular to much greater than D-parallel to), and t he decay of the collective orientational correlation function of rank two b ecame slower than that of the single particle orientational correlation fun ction of rank one. Comments on the spontaneous growth of orientational orde r directly from the isotropic phase are given.