The Orientational Ordering of Some Non‐cylindrically Symmetric Solutes in Nematic Solvents

The problem of obtaining information on the molecular properties of non‐cylindrically symmetric solute molcules in liquid crystals is examined. Nitrobenzene, tetrafluoro‐p‐benzoquinone and pyridine have been investigated in various nematic solvents at a series of temperatures using proton, fluorine and deuterium NMR where relevant. The ordering matrices for these essentially rigid molecules have been determined as a function of temperature. The predictions of a mean field theory for solutes deviating from cylindrical symmetry are considered. The relative importance of polarizability, steric forces and specific interactions in determining orientational ordering is discussed.