Molecular Polarizabilities and Orientational Ordering of Two Mesogens

The refractive indices (no, ne) and densities of two mesogens have been measured in their liquid crystalline and liquid phases. The molecular polarizabilities (xo, xe) were evaluated by Vuks' and Neugebauer's relations. The polarizabilities thus obtained are compared with those estimated from the bond polarizabilities, and the orientational order parameters, <P2>, are compared with the mean field theory of Maier and Saupe, the modified mean field theory of Humphries, James and Luckhurst. and the continuum theory suggested by T. E. Faber. We have also calculated the three order parameters (<P2), τ, σ) describing the smectic A phase following McMillan's model. Possible causes of the discrepancy are discussed.