Ordering of a monotropic nematic liquid crystal in dielectric medium at phase transition temperature: A computational analysis

Ordering in a monotropic nematic liquid crystal, 4’-n-butyl-4-cyanobiphenyl, was examined by the methods of quantum mechanics and intermolecular forces. The atomic charges and dipole moment at each atomic center were evaluated by the CNDO/2 method. The configurational energy was computed using the Rayleigh-Schrödinger perturbation method. The total interaction energies obtained by these computations were used to calculate the probability of each configuration in a dielectric medium (noninteracting and nonmessogenic solvent, benzene) at the phase transition temperature using the Maxwell-Boltzmann formula. In the dielectric medium, the energies/probabilities are redistributed, and there is a considerable rise in the probability of interactions, although the order of preference remains the same. An attempt was made to develop a new and interesting model of nematogen in a dielectric medium. A theoretical support is offered to the experimental observations.