High-frequency capillary waves at a liquid gallium surface have been studied by means of quasi-elastic light-scattering spectroscopy. The observed frequencies and damping constants of waves differed greatly from the classical theoretical treatment of a liquid Ga surface as that of a simple liquid. This effect was explained in terms of the presence of the surface layer, possessing visco-elastic properties which were, in turn, extracted, for the first time, from the fit of experimental spectra with an appropriate theoretical form. A negative value of the surface dilational viscosity has been derived for all wavenumbers studied and the effect of the visco-elasticity on the strong coupling and mixing between the capillary and dilational mode on the surface of liquid Ga has been demonstrated.
Free and oxidized surfaces of liquid mercury have been studied by means of light scattering from thermally excited capillary waves. The temperature dependence of the wave peak frequency at the free Hg surface reveals a negative derivative of the surface tension . This phenomenon is related to the spatial distribution of quasi-free electrons being much more strongly temperature dependent than the local surface ordering recently revealed at the Hg - vapour interface. The frequency observed at the Hg - HgO interface displayed two essentially different tendencies, according to the thickness of the oxide film.
High frequency capillary waves at a surface of mercury have been studied by means of quasielastic lightscattering spectroscopy. The observed damping constants of waves differ greatly from those predicted by the classical theoretical treatment of a Hg surface as that of a simple liquid. This effect is explained in terms of the presence of a surface layer of highly correlated atoms accompanying the Hg liquid-vapor transition. Viscoelastic properties of this layer are extracted from the fit of experimental spectra with a theoretical form utilizing a well known phenomenological model. The main conclusion of the present analysis is that the widely used hydrodynamic limit should be replaced by another form incorporating the Maxwell viscoelastic model.
The temperature dependence of the surface tension γ(T ) at liquid gallium is studied theoretically and experimentally using light scattering from capillary waves. The theoretical model based on the Gibbs thermodynamics relates ∂γ/∂T to the surface excess entropy density −∆S. Although capillary waves contribute to the surface entropy with a positive sign, the effect of dipole layer on ∆S is negative. Experimental data collected at a free Ga surface in the temperature range from 30 • C to 160 • C show that ∂γ/∂T changes sign near 100 • C.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.