Optical, resonant X-ray scattering, and calorimetric investigations of two liquid crystal compounds exhibiting the SmA-SmC_α*-SmC* transitions

Abstract

Three experimental measurements have been conducted to investigate the nature of the SmA–SmC_α*–SmC* phase transitions of two liquid crystal compounds. The SmA-SmC_α* transition shows a continuous transition with XY-like critical exponents. The SmC_α*-SmC* transition displays a rapid variation of the incommensurate helical pitch. One of the compounds shows a small jump in the helical pitch, which signals a first order transition and is consistent with high resolution calorimetric results.