Influence of the molecular interaction on the ac Kerr effect possibility of a field-induced phase transition

The influence of the molecular interaction on the orientation of polarizable molecules in the presence of a strong ac orienting electric field is considered. It is shown that, under certain conditions, a molecular system can be driven into a new ordered phase (similar to a liquid crystal mesophase). This first order transition leads to an orientation quite far from saturation of the molecular alignment. It is also shown that the electric field intensity required to achieve a certain induced change in the dielectric constant, via the Kerr effect, can now be much smaller than in the formulation without molecular interaction. The role of the molecular interaction in self-focusing and trapping is briefly considered.