Dynamic light scattering study of SmA-SmC*A transition in an antiferroelectric liquid crystal

A. Rastegar; Igor Musevic; Martin Copic; Theo Rasing

doi:10.1117/12.299951

1 February 1998 Dynamic light scattering study of SmA-SmC*_A transition in an antiferroelectric liquid crystal

A. Rastegar, Igor Musevic, Martin Copic, Theo Rasing

Proceedings Volume 3318, Liquid Crystals: Physics, Technology, and Applications; (1998) https://doi.org/10.1117/12.299951
Event: Liquid Crystals, 1997, Zakopane, Poland

Abstract

We have studied the order parameter dynamics close to the SmA-SmC^*_A phase transition in homeotropic cells of 4-(1-ethylheptyloxycarbonyl) phenyl-4'-alkylcarbonyloxy biphenyl-4-carboxylate by photon correlation spectroscopy. The order parameter fluctuations in the antiferroelectric SmC^*_A phase can be decomposed into the fluctuations of the phase and the amplitude of the molecular tilt angle. Considering the unit cell to consist out of two adjacent layers, one can describe these fluctuations with two ferroelectric modes and two antiferroelectric modes. Using photon correlation spectroscopy we measured both ferroelectric phase modes in the backward scattering geometry. This is the first simultaneous observation of these modes. The temperature dependence of the relaxation rates of these modes gives the coupling coefficients of the ferroelectric and antiferroelectric order parameters, whereas the dispersion relation leads to the values of the diffusivity coefficients for antiferroelectric and ferroelectric phase modes in the SmC^*_A phase.

Citation Download Citation

A. Rastegar, Igor Musevic, Martin Copic, and Theo Rasing "Dynamic light scattering study of SmA-SmC*_A transition in an antiferroelectric liquid crystal", Proc. SPIE 3318, Liquid Crystals: Physics, Technology, and Applications, (1 February 1998); https://doi.org/10.1117/12.299951

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