Computer Simulation of Ordering in 5CB and 6CB Liquid Crystals at Room Temperature: The Role of a Non-Interacting and Non-Mesogenic Solvent

Durga Prasad Ojha

《Chinese Journal of Physics》 44卷1期 (2006/02) Pp. 51-61

並列摘要

A computer simulation of ordering in a homologous series of 4-cyano-4'-alkylbiphenyls (nCB) with alkyl group pentyl (5CB) and hexyl (6CB) has been carried out with respect to translatory and orientational motions. The complete neglect of differential overlap (CNDO/2) method has been employed to evaluate the net atomic charge and atomic dipole components at each atomic centre of the molecule. The modified Rayleigh-Schrödinger perturbation theory, along with the multicentered-multipole expansion method, has been employed to evaluate the long-range intermolecular interactions, while the 6-exp potential function has been assumed for short-range interactions. The total interaction energy values obtained through these computations were used as input for calculating the probability of each configuration in a non-interacting and non-mesogenic solvent (i.e., benzene) at room temperature (300 K) using the Maxwell-Boltzmann formula. On the basis of stacking, in-plane, and terminal interaction energy calculations, all possible geometrical arrangements of molecular pairs have been considered, and the most favourable configuration of pairing has been obtained. The present article offers a theoretical support for the experimental findings.