Ab-initio electronic calculations of the directions, frequencies, and magnitudes of transition dipole moments of sub-molecular vibrational modes in chiral smectic liquid crystals
Wg. Jang, Ab-initio electronic calculations of the directions, frequencies, and magnitudes of transition dipole moments of sub-molecular vibrational modes in chiral smectic liquid crystals, J KOR PHYS, 38(4), 2001, pp. 346-355
Ab-initio density functional theory (DFT) level computations have been carr
ied out using the B3LYP/6-31G* and 6-31G** basis set to calculate the direc
tions, frequencies, and magnitudes of transition dipole moments of the sub-
molecular vibrational modes in several ferroelectric liquid crystal (FLC) c
ompounds. Polarized infrared spectroscopy of aligned smectic liquid crystal
materials also has been carried out to probe the orientational conformatio
ns of several sub-fragments of ferroelectric liquid crystal molecules. It t
urns out that thc directions of vibrational transition moments, which deter
mine primarily the polar plots of the absorbance patterns, are considerably
different from those of molecular bonds and are influenced by major atomic
interactions, such as hydrogen bondings. The calculated vibrational freque
ncies are in very good accord with the experimental values.