Structures and phase transition in a two-dimensional system of Gay-Berne molecules

We have used Percus-Yevick liquid integral equation theory and classical density functional theory of freezing to study the structure and isotropic-nematic phase transitions in a two-dimensional system of soft ellipses interacting via full Gay-Berne interaction potential. The accuracy of the pair-correlation functions given by integral equation theory has been tested by those obtained by NVT Monte-Carlo simulation. The theory is found to overestimate the structure as we move to either higher density or to the case of a longer aspect ratio. Isotropic-nematic transition parameters have been calculated for three different systems of ellipses characterized by their major to minor axis ratio kappa = 3.0, 3.5 and 4.0 at temperature T* = 2.0. The same has been calculated at T* = 1.0 for the system with kappa = 3.0. Nematic phase is found to stabilize for all the 2D systems of GB ellipses. Isotropic-nematic transition is found to be weakly first order. (C) 2019 Elsevier B.V. All rights reserved.