Ordering of fluoro-smectogen in a dielectric medium-a computational approach

A computational analysis of ordering in fluoro-smectogen, 4-propoyloxyphenyl 4-(4-trifluoromethylbenzoyloxy) benzoate (FLUORO), has been carried out with respect to translatory and orientational motions. The complete neglect differential overlap (CNDO/2) method has been employed to compute the net atomic charge and atomic dipole moment at each atomic centre. The modified Rayleigh-Schrödinger perturbation theory with the multi-centered-multipole expansion method has been employed to evaluate long-range intermolecular interactions, while a '6-exp' potential function has been assumed for short-range interactions. The interaction energy values obtained through these computations were used to calculate the probability of each configuration in a dielectric medium (i.e., non-interacting and non-mesogenic solvent, benzene) at room temperature (300 K), transition temperature (488 K) and above transition temperature (550 K). The flexibility of various configurations has been studied in terms of the variation of probability due to small departures from the most probable configuration. An attempt has been made to develop a new and interesting model of smectogen in a dielectric medium. The present investigation provides theoretical support to the experimental observations.