Simulation of nematic free surfaces

Molecular dynamics and Monte Carlo methods are applied to study the liquid free surfaces in model liquid crystals. The simulation results suggest that the attractive interactions promote parallel alignment of the molecules at the nematic free surface in the Gay-Berne model, in agreement with theoret ical predictions. A change in the orientation from planar to homeotropic is observed and explained in terms of a competing effect between attractive a nd repulsive interactions. Finally, the simulation results give clear evide nce that the hard-core repulsions favor homeotropic orientation at the nema tic free surface, in agreement with most theories.