The semi-phenomenological model of antiferroelectricity in chiral smectic liquid crystals - III. Dielectric spectroscopy

In the framework of the model of short pitch modes (SPM) developed for anti ferroelectric liquid crystals, the sets of various relaxation modes related to ferro-, antiferro- and ferri-electric phases are explained. The 'soft-l ike' modes describe the amplitude perturbations of short pitch modes, while the Goldstone modes describe the azimuthal perturbations of the molecular packings related to short pitch modes. The frequencies of the Goldstone mod es are mainly determined by the chirality parameter, depending on the numbe r of short pitch modes. The relaxation modes described correspond to the ob served phase diagrams in liquid crystal materials for which the measurement s of dielectric spectra are presented.