Theory of the dielectric susceptibility of polar liquid crystals

Statistical theory of the dielectric susceptibility is derived in the case of polar uniaxial molecules. The orientational and the induced parts of the susceptibility are taken into account. A generalized Claussius-Mossotti approach is used and the reaction field of the dipole moments is neglected (the low density limit). It is explained, in the case of prolate molecules, why the commonly used Maier and Meier formula overestimate the susceptibility component along the phase symmetry axis. Exemplary calculations of the temperature dependence of the order parameters and the susceptibility are presented.