Abstract
Alignment of molecules and hindered rotation of molecular segments in SmCp* and SmC* of antiferroelectric and ferroelectric liquid crystals were studied by the polarized infrared absorption spectroscopy. The experimental results show that the apparent molecular tilt angle in SmCβ* increases not monotonously but as a two-step staircase with increasing dc bias field, and the characteristics of hindered rotation of carbonyl groups in unwound state of helix are the same as that of SmC*.