| Abstract: | Polarized FTIR measurements have been made on four ferroelectric liquid crystal compounds which have a large spontaneous polarization; two of them have a hydroxyl group that can form a hydrogen bond. Particular attention was given to three C-O stretching peaks: keto, ester, and lactic acid. We found that the polar absorbance pattern and peak positions of the keto C-O group stretching vibration are clearly different in compounds with and without the hydroxyl group. We have succeeded in interpreting these measurements by calculating IR transition moment directions for the vibrational modes of several model compounds using quantum chemical methods, including HF/6-311G SCF and B3LYP/6-31G(d) and B3LYP/6-31G(d,f) DFT calculations. Rotational bias was clearly observed even in the ester C-O group in the molecular core in the SmC* phase of the compound with a hydrogen bond. |
