Quasielectric Rayleigh Scattering in a Smectic-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>C</mml:mi></mml:math>Liquid Crystal

Abstract

Using light-beating spectroscopy, we observe the Rayleigh scattering from a smectic-$C$ monodomain of $\mathrm{d}\mathrm{i}\ensuremath{-}(4\ensuremath{-}n\ensuremath{-}\mathrm{d}\mathrm{e}\mathrm{c}\mathrm{y}\mathrm{l}\mathrm{o}\mathrm{x}\mathrm{y}\mathrm{b}\mathrm{e}\mathrm{n}\mathrm{z}\mathrm{a}\mathrm{l})\ensuremath{-}2\ensuremath{-}\mathrm{c}\mathrm{h}\mathrm{l}\mathrm{o}\mathrm{r}\mathrm{o}\ensuremath{-}1\ensuremath{-}4\ensuremath{-}\mathrm{p}\mathrm{h}\mathrm{e}\mathrm{n}\mathrm{y}\mathrm{l}\mathrm{e}\mathrm{n}\mathrm{e}\phantom{\rule{0ex}{0ex}}\mathrm{d}\mathrm{i}\mathrm{a}\mathrm{m}\mathrm{i}\mathrm{n}\mathrm{e}$. The signal is attributed to thermally excited relative rotations of smectic layers as proposed by de Gennes. We discuss the anisotropy of the elastic and viscosity coefficients involved in this mode, by comparison with the nematic situation.