Molecular Polarizability Studies on 12. CB, 7O. CB Cyano-biphenyl Liquid Crystal by Theoretical and Experimental Approach

Rihana Banu

Abstract: The transition temperatures of Cyano-biphenyl liquid crystalline compounds, (12.CB, 7O.CB) are recoded by using Differential scanning calorimeter. The transition temperatures are used to estimate molecular polarizability by theoretical approaches. I.e. by quantum dynamical- ? function model and molecular vibration method. The density and refractive indices are measured by using specially designed Pyknometer and indegeneously developed spectrometer coupled with small angled prism the molecular polarizabilities are evaluated by Vuks and Neugebauer methods using experimentally obtained refractive indices and density data. The results obtained from these methods are compared from one another and the limitations of this methods are discussed.

Keywords: Liquid crystals, Phase transition temperatures, density, refractive indices, and molecular polarizabilities