Order Parameters and Distribution in the Smectic Layer of Probe Molecules Dissolved in Ferroelectric Liquid Crystalline Mixtures

Abstract

For a few types of relatively small probe molecules with different sizes and geometrical anisotropies, alignment-induced ¹³C chemical shifts or spacings in the multiplet due to the residual dipolar interaction are measured in the anisotropic S_A and S_C^* phases of ferroelectric liquid crystals. On the basis of the simplified motional model, the orientational order parameter and the tilt angle are determined for the probes and compared with those of the liquid crystal itself. The tilt angles of the probes are fairly similar to those of liquid crystals. Various types of temperature variations of the orientational order are discussed in terms of the mobility and spatial distribution of the probe molecules in the smectic layers in relation to the expulsion of the probes from the rigid core region in the liquid crystal.