Experimental investigations of one liquid-crystal compound exhibiting the no-layer-shrinkage effect near the Sm-A-Sm- C(*) transition.

Three experimental probes have been employed to investigate the nature of the smectic-$A$--smectic-$C$ ($\text{Sm}\text{\ensuremath{-}}A--\text{Sm}\text{\ensuremath{-}}{C}^{*}$) phase transition of one liquid-crystal compound showing almost no layer-shrinkage effect through the transition. Results from both x-ray diffraction and optical studies indicate that the compound exhibits a crossover behavior of different molecular packing arrangements within the bulk $\text{Sm}\text{\ensuremath{-}}A$ phase window. The calorimetry results show a significant critical anomaly near the $\text{Sm}\text{\ensuremath{-}}A--\text{Sm}\text{\ensuremath{-}}{C}^{*}$ transition, although it was found to be weakly first order.