Reaction Field Method for the Molecular Orientation Potential in an Anisotropic Medium

摘要

The molecular orientation potential in an anisotropic medium was studied using (he reaction field method. The interaction energy between a molecule and an anisotropic medium was calculated using the dielectric anisotropy as a perturbation parameter. We have investigated the influence of molecular geometry on the molecular orientation potential using biphenyl and lerphenyl, which constitute cores of liquid crystal molecules. We have calculated the barrier height for the molecular rotation changing thetwist angle between phenyl rings, using an ab initio molecular orbital method. We have found that the torsional motion of the phenyl rings affects the orientation potential, and that deviation from the molecular cylindrical symmetry lowers the saddle point for the rotation.