Effect of the smectic-<i>A</i>temperature range on the behavior of the smectic-<i>A–</i>smectic-<i>C</i>(or<i>–</i>chiral-smectic-<i>C</i>) transition

Abstract

First we demonstrate that the extended mean-field model suggested by Huang and Viner is necessary and sufficient to describe the nature of the smectic-A--smectic-C (or --chiral-smectic-C) transition. The rest of the expansion terms in the mean-field free energy can be treated as higher-order correction terms. Then a general scheme is proposed to normalize the smectic-C (or chiral smectic-C) order parameter. As a result, the mean-field coefficients near the smectic-A--smectic-C (or --chiral-smectic-C) transition are found to vary systematically with the size of the smectic-A temperature range for all single-component liquid-crystal compounds with smectic-A--smectic-C (or --chiral-smectic-C) transition.