Computer simulation of liquid crystals

Computer simulations. using the molecular dynamics and Monte Carlo techniques, and employing simple molecular models, yield insight into general features of phase equilibria, structure. and dynamics of liquid crystals. Here, results are reported from extensive simulations of the Gay-Berne family of molecular models, in which potential parameters are adjusted to vary the molecular length-to-width ratio in a systematic way. Attention is paid to the characterization of nematic, smectic-A and smectic-B phases as functions of these parameters. A simulation study of the approach to the isotropic-nematic phase transition, using a large system size and lengthy runs on the T3D parallel supercomputer, is described. Spatially long-ranged collective orientational correlations develop in the isotropic phase, close to the transition. The direct correlation function has been calculated for these systems, and remains short-ranged, as expected, as the transition is approached. The simulation results are compared with the density functional analysis of isotropic instability relative to the nematic phase.