Dielectric Relaxation in Polar Liquid Crystals

A model is suggested for interpreting the experimental dielectric dispersion data in nematic liquid crystals. The high‐frequency dispersion is observed in both, parallel and perpendicular alignment of substances with only a molecular dipole moment parallel to the long axis of the molecule. In the absence of a perpendicular dipole moment component these high‐frequency absorptions cannot be associated with rotation about the molecular axis. The model is based on Kubo's linear response theory and describes the dipole relaxation processes in frames of rotational diffusion. Results are compared with experimental data obtained on 4‐cyano‐4′‐octylbiphenyl.