Obliquely projecting chiral alkyl chains and their precession around the long core axes in the smectic-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>A</mml:mi></mml:math>phase of an antiferroelectric liquid crystal

Abstract

By deuterizing the chiral and achiral alkyl chains separately, we have observed the ir absorbance vs polarizer rotation angle for the C${\mathrm{H}}_{2}$ and phenyl ring stretching peaks in a prototype antiferroelectric liquid crystal, 4-(1-methylheptyloxycarbonyl) phenyl 4\ensuremath{'}-octyloxybiphenyl-4-carboxylate (MHPOBC). The angle between the chiral chain and core axes is more than 54.7\ifmmode^\circ\else\textdegree\fi{} (the magic angle) even in the smectic-$A$ (Sm-$A$) phase and the precession appears to be biased or hindered toward the tilt-plane normal in the chiral smectic-$C$ (Sm-${C}^{*}$) phase.