Computer simulation studies of anisotropic systems: XXIII. The Gay-Berne discogen† Presented at the European Liquid Crystal Conference, Flims, Switzerland, 8–12 March 1993.

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 ρ* 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.

[1]  C. M. Care,et al.  Molecular dynamics simulations of discotic liquid crystals using a hybrid Gay–Berne Luckhurst–Romano potential , 1994 .

[2]  G. R. Luckhurst,et al.  Computer simulation studies of anisotropic systems: XXI. Parametrization of the Gay-Berne potential for model mesogens , 1993 .

[3]  G. R. Luckhurst,et al.  Computer simulation studies of anisotropic systems. XX: On the validity of the Maier-Saupe approximations for the Gay-Berne nematogen , 1992 .

[4]  G. R. Luckhurst,et al.  Computer simulation studies of the dependence on density of the orientational order in nematic liquid crystals , 1992 .

[5]  L. F. Rull,et al.  A Molecular Simulation of A Liquid-crystal Model , 1991 .

[6]  L. F. Rull,et al.  LOCATION OF THE ISOTROPIC-NEMATIC TRANSITION IN THE GAY-BERNE MODEL , 1991 .

[7]  G. R. Luckhurst,et al.  Computer simulation studies of anisotropic systems. XIX. Mesophases formed by the Gay-Berne model mesogen , 1990 .

[8]  J. Talbot,et al.  A comparison between molecular-dynamics and theoretical results for the structure of fluids of hard ellipsoids , 1990 .

[9]  G. Patey,et al.  Fluids of dipolar hard ellipsoids: Structural properties and isotropic–nematic phase transitions , 1989 .

[10]  G. R. Luckhurst,et al.  Computer simulation studies of anisotropic systems: XVII. The Gay-Berne model nematogen , 1987 .

[11]  D. Frenkel.  Computer simulation of hard-core models for liquid crystals , 1987 .

[12]  C. Zannoni,et al.  A Monte Carlo investigation of the Lebwohl-Lasher lattice model in the vicinity of its orientational phase transition , 1986 .

[13]  R. Eppenga,et al.  Monte Carlo study of the isotropic and nematic phases of infinitely thin hard platelets , 1984 .

[14]  B. Berne.  Modification of the overlap potential to mimic a linear site-site potential , 1981 .

[15]  K. A. Suresh,et al.  Liquid crystals of disc-like molecules , 1977, Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences.

[16]  Bruce J. Berne,et al.  Computer simulation of anisotropic molecular fluids , 1976 .

[17]  Jacques Vieillard-Baron,et al.  The equation of state of a system of hard spherocylinders , 1974 .

[18]  Bruce J. Berne,et al.  Gaussian Model Potentials for Molecular Interactions , 1972 .

[19]  Andrew P. J. Emerson,et al.  Monte Carlo investigations of a Gay—Berne liquid crystal , 1993 .

[20]  Daan Frenkel,et al.  Columnar ordering as an excluded volume effect , 1989 .