Capillary waves at the liquid-vapor interface and the surface tension of water models

摘要

Capillary waves occurring at the liquid-vapor interface of water are studiedusing molecular dynamics simulations. In addition, the surface tension,determined thermodynamically from the difference in the normal and tangentialpressure at the liquid-vapor interface, is compared for a number of standardthree- and four-point water models. We study four three-point models (SPC/E,TIP3P, TIP3P-CHARMM, and TIP3P-Ew) and two four-point models (TIP4P andTIP4P-Ew). All of the models examined underestimate the surface tension; theTIP4P-Ew model comes closest to reproducing the experimental data. The surfacetension can also be determined from the amplitude of capillary waves at theliquid-vapor interface by varying the surface area of the interface. Thesurface tensions determined from the amplitude of the logarithmic divergence ofthe capillary interfacial width and from the traditional thermodynamic methodagree only if the density profile is fitted to an error function instead of ahyperbolic tangent function.