The relationship between molecular symmetry and second-rank orientational order parameters for molecules in chiral liquid crystalline solvents

From group theoretical arguments, we demonstrate that the effective molecular symmetry is reduced in a chiral liquid crystalline phase. This reduction changes the location of the principal axes of the orientational order matrices for four molecular point groups, namely C-s, C-2 upsilon, S-4, and D-2d. These symmetries correspond to compounds which have prochiral faces, groups, or directions. The change in effective molecular symmetry can be detected by NMR spectroscopy, and this is illustrated by the example of acenaphthene dissolved in a chiral nematic solvent. (C) 1999 American Institute of Physics. [S0021-9606(99)51937-5].