%0 Journal Article %T Density Profiles of Liquid/Vapor Interfaces Away from Their Critical Point %A Wei Bu %A Doseok Kim %A David Vaknin %J Physics %D 2014 %I arXiv %X We examine the applicability of various model profiles for the liquid/vapor interface by X-ray reflectivities on water and ethanol and their mixtures at room temperature. Analysis of the X-ray reflecivities using various density profiles shows an error-function like profile is the most adequate within experimental error. Our finding, together with recent observations from simulation studies on liquid surfaces, strongly suggest that the capillary-wave dynamics shapes the interfacial density profile in terms of the error function. %U http://arxiv.org/abs/1403.1469v2