D. Ojha
Mar 7, 2005
Citations
0
Influential Citations
5
Citations
Journal
Journal of Molecular Structure-theochem
Abstract
Abstract A comparative statistical analysis of molecular ordering of smectogenic compounds, 3-[2-(perflurooctyl) ethoxy] nitrobenzene (FLUORO1) and ethyl 4-[2-(perfluorooctyl) ethoxy] benzoate (FLUORO2), has been carried out on the basis of quantum mechanics and intermolecular forces. The evaluation of atomic charge and dipole moment at each atomic centre has been carried out through an all-valence electron (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 in dielectric medium (i.e. non-interacting and non-mesogenic solvent, benzene) 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. It has been observed that energies are redistributed in dielectric medium and there is considerable rise in the probability of interaction, although the order of preference remains the same. This provides theoretical support to the experimental observations.