Rayleigh Linewidth in Xenon Near the Critical Point
Abstract
The Rayleigh linewidth $\ensuremath{\Gamma}$ of xenon was measured on the critical isochore between 0.003 and 5.0\ifmmode^\circ\else\textdegree\fi{}C above ${T}_{c}$. In the hydrodynamic region ($q\ensuremath{\xi}<~0.2$) we find $\ensuremath{\Gamma}={q}^{2}{\ensuremath{\chi}}_{0}{[\frac{(T\ensuremath{-}{T}_{c})}{{T}_{c}}]}^{\ensuremath{\gamma}\ensuremath{-}\ensuremath{\psi}}$ with ${\ensuremath{\chi}}_{0}=(6.94\ifmmode\pm\else\textpm\fi{}0.21)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ ${\mathrm{cm}}^{2}$/sec, and $\ensuremath{\gamma}\ensuremath{-}\ensuremath{\psi}=0.751\ifmmode\pm\else\textpm\fi{}0.004$. Our data over the entire region $0.009<~q\ensuremath{\xi}<~6.7$ agree quite well with the recent Kawasaki extended mode-mode coupling theory. However, the Kadanoff-Swift-Kawasaki result $\ensuremath{\gamma}\ensuremath{-}\ensuremath{\psi}=\ensuremath{\nu}$ does not appear to be valid.