The Landau free energy of hard ellipses obtained from microscopic simulations

Luo, A. M., Sagis, L. M. C. and Ilg, P. ORCID: https://orcid.org/0000-0002-7518-5543 (2014) The Landau free energy of hard ellipses obtained from microscopic simulations. The Journal of Chemical Physics, 140. 124901. ISSN 0021-9606 doi: 10.1063/1.4868988

Abstract/Summary

Systems of two-dimensional hard ellipses of varying aspect ratios and packing fractions are studied by Monte Carlo simulations in the generalised canonical ensemble. From this microscopic model, we extract a coarse-grained macroscopic Landau-de Gennes free energy as a function of packing fraction and orientational order parameter. We separate the free energy into the ideal orientational entropy of non-interacting two-dimensional spins and an excess free energy associated with excluded volume interactions. We further explore the isotropic-nematic phase transition using our empirical expression for the free energy and find that the nature of the phase transition is continuous for the aspect ratios we studied.