Dipole-induced ordering in nematic liquid crystals fact or fiction?

Similar size and shape molecules with different electric multipoles are used to investigate effects of dipole and quadrupole interactions on the average orientation of solutes in nematic liquid crystals. Permanent dipoles have a negligible influence on solute orientation. Order parameters predicted from strong, short-range repulsive forces coupled with interactions between the solute quadrupole and the average electric field gradient felt by the solute 〈EFG〉 are consistent with experimental values. Calculated 〈EFG〉ʹs are the same sign and similar magnitude to those determined previously from D2 and HD. For the nematic mixture 55wt% ZLI 1132 in EBBA, the contribution to solute ordering from long-range electrostatic interactions is negligible.