COMPUTER-SIMULATION STUDIES OF ANISOTROPIC SYSTEMS .23. THE GAY-BERNEDISCOGEN

The Gay-Berne potential has been employed extensively in simulation st udies of rod-like liquid crystals. However, the potential can be used also to study discotic liquid crystals, that is, compounds whose molec ules are flattened or disc-shaped. Here we suggest a suitable parametr ization for Gay-Berne discs and report the results of some constant vo lume 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 i n the simulation. At a scaled density rho of 3.0 the columns are obse rved 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 interdi gitation between the columns at the higher density.