Phase organization in laterally substituted dicyclohexylethane derivatives—A molecular model for smectogens

Abstract

The present article deals with the configurational probabilities of smectogens 1, 2-bis (4-pentylcyclohexyl) ethan-1-ol (PCHE1) and 1, 2-bis (4-pentylcyclohexyl) ethan-1-one (PCHE2) with respect to translational and orientational motions. The complete neglect differential overlap (CNDO/2) method has been employed to compute the net atomic charge and atomic dipole moment components at each atomic center. The modified Rayleigh–Schrodinger perturbation theory along with multicentered-multipole expansion method has been employed to evaluate the long-range intermolecular interactions, while a ‘ 6-exp’ potential function has been assumed for short-range interactions. The total interaction energy values obtained through these computations have been used to calculate the configurational probability at smectic B-isotropic transition temperature using the Maxwell–Boltzmann formula. Molecular arrangements inside a bulk of materials and smectic behavior of the compounds in terms of their relative order have been discussed. Further, a model has been developed at molecular level to understand the effect of translational/rotational rigidity on phase organization and relative flexibility of one configuration over the other.