Structure Analysis in the Hexatic Antiferroelectric Sml_A^* Phase by X-ray diffraction and NMR Spectroscopy

Abstract

In order to investigate the structure in the hexatic SmI_A^* phase, we measured the higher order X-ray Bragg reflections corresponding to the layer spacing and NMR spectra. Although the optical tilt angle is alomost constant at the SmC_A^*-SmI_A^* phase transition, the layer spacing increases and the third order peak becomes larger than the second one. We found that the chemical shift assigned to the alkyl crabon at the chiral side does not change by MAS measurement, and it indicates that the layer spacing change results from the molecular reoriertation in a layer at the transition.