Dielectric dispersion in a dual-frequency nematic liquid crystal 2-chloro-4-(4-pentylbenzoyloxy)benzoate

Temperature dependences of dielectric dispersions in the homogenous and homeotropic alignment cells of 2-chloro-4-(4-pentylbenzoyloxy)benzoate (PCPB) were measured in the nematic phase in the frequency range between 100 Hz and 1 MHz. The obtained dielectric dispersions, e'(ω) and e''(ω), could be explained using the Cole–Cole formula accounting for DC conduction. The parameter values in this formula were determined by the least-squares method. The frequency dependence of the dielectric anisotropy, including the dual-frequency characteristic, was well reproduced with our parameter values. The activation energy E a for molecular reorientation was estimated as approximately 9 × 102 meV. The crossover frequency f c was approximately proportional to the relaxation frequency f r in PCPB.