Mesomorphic Ordering in Liquid Crystalline Materials (BCHs) – A Computational Study Based on Intermolecular Interactions

A computational study of mesomorphic ordering in liquid crystalline disubstituted biphenyl cyclohexanes (BCHs) of general formula R-C₆H₁0-C₆H₄-X with R: C₃H₇; X: H (BCH₃0) and R: C₅H₁1; X: CN (BCH5CN) has been carried out with respect to translational and orientational motion. The atomic net charge and dipole moment at each atomic center were evaluated using the complete neglect differential overlap (CNDO/2) method. The modified Rayleigh-Schrodinger perturbation theory and the multicenter-multipole expansion method were employed to evaluate long-range intermolecular interactions, while a 6-exp potential function was assumed for short-range interactions. Various possible geometrical arrangements of molecular pairs with regard to different energy components were considered. A comparative picture of molecular parameters, such as total energy, binding energy, and total dipole moment of BCH5CN with BCH30 is given. The present computations are helpful in establishing the liquid crystalline behaviour in terms of molecular forces.