A comparison of orientational behaviour and rotational bias in SmC*, SmC_a* and SmC_γ* phases of an antiferroelectric liquid crystal studied by FT-IR spectroscopy

Abstract

Polarised infrared Spectroscopy is used to study the behaviour of SmC*, SmC_A* and SmC_γ* phases of an antiferroelectric liquid crystal material. The degree of molecular orientation is expressed in terms of the dichroic ratio obtained from the absorbance profiles for various applied voltages. The molecular tilt angle is found as the absorbance profiles of the various peaks rotate clockwise and anticlockwise with the sign of the applied field. The absorbance profiles of the stretching bands are quantitatively analysed and the biasing parameters of the transition dipole moments located in the molecular core for each phase are calculated and compared.

Keywords:

• infrared Spectroscopy
• antiferroelectric liquid crystal
• switching