Abstract
Starting with a model intermolecular potential that includes terms to account for anisotropic steric interactions, we carry out a statistical mechanical calculation in the cell approximation, and apply it specifically to the isotropic-nematic transition of methoxybenzylidene butylaniline (MBBA). The potential is determined to fit the experimental transition temperature and the discontinuity in the orientational order parameter at transition. and are then calculated from solving a set of coupled self-consistency equations for the orientational and spatial parts of the distribution function, as are other phase-transition properties. There are improvements over model calculations which do not account for anisotropic steric effects, but the improvements are generally less than significant. The most striking result is that a stable nematic phase requires to be negative at and near the transition. It is a theoretical result qualitatively consistent with experimental data but has not been attained until now.
- Received 17 August 1982
DOI:https://doi.org/10.1103/PhysRevA.28.1587
©1983 American Physical Society