Light Scattering from Surface Waves on Carbon Dioxide Near the Critical Point

The spectrum of light scattered from surface waves thermally excited on the liquid-vapor interface of carbon dioxide has been measured at several scattering angles in the temperature range $30°>~T_c-T>~3.5\times {10}^{-2\mathrm{}}°$K. Within experimental error no deviation of the spectrum shape from the predictions of thermodynamic fluctuation theory is observed. The temperature dependence of the surface tension is deduced from the data and fitted by the empirical law $\alpha ={\alpha }_0{(1-\frac{T}{T_c})}^{\mu }$, with $\mu =1.253\mathrm{}\pm 0.010$ and ${\alpha }_0=17.9\mathrm{}\pm 1.2$ dyn/cm. No anomaly is noticed in the temperature variation of the shear viscosity.