Microscopic description in the Gaussian approximation of the nematic-isotropic phase transition

Abstract

The nematic-isotropic phase transition of a system of nonpolar rodlike molecules is considered. The mean-field theory is extended to take into account the local field fluctuations in the Gaussian approximation. The calculations are performed in the five-dimensional space of the order-parameter components. The numerical results are obtained for the lattice system of molecules and compared with the calculations in the mean-field theory, cluster approximation, and Monte-Carlo simulation data.