On Dielectric Relaxation in Liquid Crystals

A general expansion of the orientational distribution function in terms of the Wigner matrix is employed in order to calculate dipole moment correlation functions in liquid crystals. It is shown that the qualitative interpretation of dielectric relaxation spectra of liquid crystals is possible without explicit characterization of the molecular motions involved. Thus, a wide range of stochastic motions can be considered within the framework of the model. A fundamental influence of the orientational order of molecules in the liquid-crystalline state on the qualitative form of dielectric spectra is emphasized.