Correlation between dielectric and optical measurements in the smectic-Cα* phase -: art. no. 031709

We present optical and dielectric measurements in the smectic-C-alpha(*) (SmCalpha*) phase of three homologues of an alkoxy benzoate series. Two different behaviors are observed depending on the values and the temperature evolution of the azimuthal angle difference alpha between two adjacent layers. For moderate values of alpha, the Goldstone mode is predominant over the whole SmCalpha* phase. For large values of alpha, we can distinguish the soft mode near the SmA(*)-SmCalpha* phase transition and the Goldstone mode at lower temperatures. In this case, discontinuities are also observed at the SmCalpha*-SmA(*) phase transition. These dielectric features are correlated with optical properties using simulations based on the discrete phenomenological "clock model."