Observation of capillary waves on liquid thin films from mesoscopic to atomic length scales

The surfaces of liquid thin perfluorohexane, cyclohexane, decane, and ethan ol films adsorbed on silicon wafers have been investigated by means of x-ra y reflectivity, diffuse scattering, and grazing incidence diffraction. The measurements prove that the surface structure of the wetting films can be d escribed by a universal height-height correlation function derived from a c apillary wave model with the: surface tension and particular cutoffs as par ameters. The data favor a reduced capillary wave surface tension as predict ed by exact theories, over an enhanced capillary wave surface tension, as s uggested by simple mode-coupling models.