Preliminary communication - A possible structural model of the SmC beta* phase

The so-called chiral smectic C-beta (SmCbeta*) phase has been reported as d istinct from the SmC* phase in several materials that exhibit antiferroelec tric liquid crystal mesophases and subphases. The SmCbeta* phase is known t o be chiral, tilted and to exhibit ferrielectric switching, but no structur e had been suggested which explains these effects. This paper presents a po ssible structure for the SmCbeta* phase which can explain the ferrielectric properties. The model is proposed on the basis of complementary optical, e lectric and X-ray diffraction studies of a chiral liquid crystal. The layer spacing, optical and steric tilt and spontaneous polarization over the tem perature range of the SmCbeta* phase are described. The complementary exper imental techniques used reveal the occurrence of inversion phenomena, on wh ich this model is based.