Polarized FT-IR study on SmC beta* and SmC* of antiferroelectric liquid crystals

Alignment of molecules and hindered rotation of molecular segments in SmCbe ta* and SmC* of antiferroelectric and ferroelectric liquid crystals were st udied by the polarized infrared absorption spectroscopy. The experimental r esults show that the apparent molecular tilt angle in SmCbeta* increases no t monotonously but as a two-step staircase with increasing de bias field, a nd the characteristics of hindered rotation of carbonyl groups in unwound s tate of helix are the same as that of SmC*.