Studies on the Molecules Structure of an Antiferroelectric Liquid Crystal Using Two-dimensional Polarized Infrared and Raman Spectroscopy

Polarization angle-dependent infrared and Raman spectra of an antiferroelectric liquid crystal in the S_(CA)~* phase were measured at 78℃ for investigating the molecular conformation and arrangement. Two-dimensional (2D) correlation spectroscopy had been applied to analyze the polarization angle dependence of band intensity changes. The CH_3 asymmetric and symmetric stretching bands adjacent the chiral part was separated by 2D correlation spectroscopy into those arising from other methyl groups in the alkyl chains. And it was found that the s-cis and the s-trans isomers of the ester group coexist in the S_(CA)~* phase.