Analysis of the Circular Dichroism Behavior of Some Disubstituted Benzenes in Cholesteric Mesophases

The preferred alignment of some disubstituted benzenes in a cholesteric mesophase has been determined by the liquid crystal induced circular dichroism (LCICD) technique. The sign of the LCICD of the 1Lb ← 1A electronic transition of known polarization was used to establish the sign of the order parameter (S), for a defined molecular axis, of the ordered benzene derivative. The preferred alignment as deduced from LCICD studies agrees with that obtained from more detailed nmr investigations on related compounds.