Wavelength Dependence of Liquid-Vapor Interfacial Tension of Ga

Abstract

The wave-vector dependence of the liquid-vapor interfacial tension of Ga, $\ensuremath{\gamma}(q)$, has been determined from diffuse x-ray scattering measurements. The ratio $\ensuremath{\gamma}(q)/\ensuremath{\gamma}(0)=1$ for $q<0.05\text{ }{\AA{}}^{\ensuremath{-}1}$ decreases to 0.5 near $q=0.22\text{ }{\AA{}}^{\ensuremath{-}1}$, and increases strongly for larger $q$. The observed form for $\ensuremath{\gamma}(q)/\ensuremath{\gamma}(0)$ is consistent with the prediction from the Mecke-Dietrich theory when the known stratified liquid-vapor interfacial density profile of Ga and a pseudopotential based pair interaction with appropriate asymptotic ($r\ensuremath{\rightarrow}\ensuremath{\infty}$) behavior are used. The detailed behavior of $\ensuremath{\gamma}(q)/\ensuremath{\gamma}(0)$ depends on the particular forms of both the interfacial density profile and the asymptotic falloff of the atomic pair interaction.