Ordering of smectogenic compounds - A statistical approach based on quantum mechanics and computer simulation

A statistical analysis of molecular ordering of smectogenic compounds, 3-[2-(perflurooctyl) ethoxy] nitrobenzene (FLUORO1) and ethyl 4-[2-(perfluorooctyl) ethoxy] benzoate (FLUORO2), have been carried out with respect to translatory and orientational motions. The net atomic charge and atomic dipole components at each atomic center of the molecule has been evaluated using the CNDO/2 method. The Rayleigh-Schrodinger perturbation theory, along with the multicentered-multipole expansion method, has been employed to evaluate the long-range intermolecular interactions while "6-exp" potential function is assumed for short-range interactions. The total interaction energy values obtained through these computations were used to calculate the probability of each configuration at its phase transition temperature using the Maxwell-Boltzmann formula. The flexibility of various configurations has been studied in terms of variation of probability due to small departures from the most probable configuration. The results obtained have been correlated with the parameters introduced in this article.