Location of the isotropic-nematic transition in the Gay-Berne model

Molecular dynamics computer simulations have been carried out on a system consisting of cylindrically symmetric molecules with length-to-breadth ratio k = 3 and well depth ratio k′ = 5 interacting through the Gay-Berne potential. For this system we have located the coexistence points corresponding to the isotropic-nematic transition by calculating the absolute free energy of each phase. Two temperatures, T* = 1·25 and 0·95, have been studied. In each case a weak first-order phase transition has been found, with a density change close to 2·5%. The isotropic-nematic coexistence densities are found to increase with increasing temperature.