COMPUTER-SIMULATION STUDIES OF ANISOTROPIC SYSTEMS .23. THE GAY-BERNE DISCOGEN

The Gay-Berne potential has been employed extensively in simulation studies of rod-like liquid crystals. However, the potential can be used also to study discotic liquid crystals, that is, compounds whose molecules are flattened or disc-shaped. Here we suggest a suitable parametrization for Gay-Berne discs and report the results of some constant volume molecular dynamics simulations. The system is shown to exhibit an isotropic, a discotic-nematic and a columnar phase. The structure of the columnar phase is found to depend critically on the density used in the simulation. At a scaled density rho* of 3.0 the columns are observed to pack in a rectangular manner while at the lower density of 2.5, the more usual hexagonal array is seen. The difference in structure of the two columnar phases is shown to be due to the increased interdigitation between the columns at the higher density.