Computer Simulation Studies of Anisotropic Systems IV. The Effect of Translational Freedom

摘要: We have simulated the properties of 256 cylindrically symmetric particles interacting via a simple anisotropic potential form u$\_2$ (r$\_{12}$) P$\_2$(cos $\beta\_{12}$) and with scalar Lennard-Jones 12:6 potential, using Monte Carlo technique. The simulations were performed for two forms u$\_2$(r$\_{12}$) in isothermal-isobaric ensemble yielded values volume, enthalpy, second-rank orientational order parameter, radial distribution function angular correlation function. specific heat at constant pressure, isothermal compressibility isobaric expansivity also obtained but they are subject to considerable error because evaluated from fluctuations. system is found exhibit weak, firstorder transition nematic an isotropic phase on increasing temperature. possesses short-range spatial order; it differs phase, which has long-range only order. results these used discuss influence range behaviour nematogen. Previous liquid crystals had employed lattice model interactions restricted nearest neighbours. Our study effect convenient unrealistic restrictions nematic. our reasonable accord nematogen, 4,4$'$-dimethoxyazoxybenzene, although no attempt was made select pair mimic any substance. Finally, we use test validity molecular field approximation, as applied nematics. This approximation one foundations Maier-Saupe theory its predictions compared It would appear that this provides better description than model, enforced truncated potential.