Calculation of Dielectric and Optical Anisotropy of Nematic Cyanoethylene and Cyanobutadiene Derivatives

Abstract

We have synthesized compounds with the general chemical structure

By quantum chemical methods the polarizability and its anisotropy, the electrical dipole moment and its angle with the molecular long axis have been calculated. The molar volumes have been determined using group contribution methods. For the determination of the order parameter an empirical relation to the clearing temperature has been developed. Using these data, by the theory of Maier and Meier the dielectric and optical anisotropy have been calculated. The comparison with experimental data shows, that the method works with an accuracy acceptable for industrial application.

Key Words:

• dielectric constants
• refractive indices
• order parameter
• semiempirical calculations
• nematics