A grazing incidence x-ray diffraction study of the transverse structure function of the liquid–vapor interface of Ga

We report the results of a grazing incidence x-ray diffraction study of the liquid–vapor interface of Ga. It is shown that the transverse structure function in the liquid–vapor interface of Ga is indistinguishable from the structure function of bulk liquid Ga. When compared with the transverse structure functions obtained from calculations of models of the liquid–vapor interface of a similar system [J. Chem. Phys. 86, 1036 (1987)], this result implies that the widely used point local density approximation to the properties of an inhomogeneous liquid is inaccurate and must be replaced by a representation which includes, at least to first order, the effect of the force which generates the density inhomogeneity in the liquid.