Rayleigh linewidth and thermal conductivity of SF6 in the supercritical range

The Rayleigh linewidth of SF6 along the critical isochore and its thermal conductivity coefficient as a function of temperature and pressure have been measured. The decay rate of the density fluctuations is asymptotically well described by the Kawasaki mode–mode coupling theory without any adjustable parameters, and a small systematic deviation between theory and experiment is observed away from the critical point.