Monte Carlo simulations of polar discotic molecules

Abstract

The orientational order in the fluid and liquid crystal phases of a simple model of dipolar discotic molecules (cut-spheres) is determined by Monte Carlo simulations. Our results are mainly directed to a qualitative study of this ordering in view of the long relaxation times of metastable states in the dense liquid crystal phases. In the fluid and nematic phases, short columns of five molecules are found to be the most probable arrangements of neighbouring molecules. In the columnar phase the dipole-dipole interactions can induce the polarization of the columns which are arranged with antiferroelectric order. When the orientation of the dipole moment breaks the axial symmetry of the molecules, a rectangular columnar phase with molecules tilted with respect to the columnar axis appears to be the stable dense liquid crystal phase.