Structure of the chiral smectic-C-alpha(*) phase

Ellipsometric measurements of freely suspended films of a chiral liquid-cry stal compound possessing the phase sequence smectic-A-smectic-C-alpha*-smec tic-C* have been conducted in order to elucidate the structure of the smect ic-C-alpha* phase. The measured ellipsometric quantities Delta and Psi are compared with values, which were calculated for model films using the 4X4 m atrix method. Our results confirm, for the compound under investigation, pr edictions of a phenomenological model [M. Cepic and B. Zeks, Mel. Cryst. Li q. Cryst. 263, 61 (1995)] according to which the smectic-C-alpha* phase is characterized by a short-pitch helical structure. [S1063-651X(99)16711-4].