DIFFUSION-COEFFICIENT INCREASES WITH DENSITY IN HARD ELLIPSOID LIQUID-CRYSTALS

Molecular-dynamics simulations of highly nonspherical rodlike and platelike molecules reveal that one of the two diffusion coefficients in the nematic-liquid-crystal phase increases with density, reaches a maximum, and decreases, while the other coefficient decreases monotonically in the usual way. This effect seems to be associated with the density variation of the nematic order parameter near the phase transition. A kinetic theory based on isolated binary collisions significantly underestimates the diffusion coefficients, but partially accounts for the enhancement effect. © 1990 The American Physical Society.