Liquid-vapor interface, cavitation, and the phase diagram of water

The study of the liquid-vapor interface and of the cavitation phenomenon in water can give deeper insight in its metastable phase diagram. We show how two different equations of state proposed for water, combined with the van der Waals-Cahn-Hilliard theory of a nonuniform system, lead to qualitatively different predictions. In particular, the thickness of the liquid-vapor interface is found either to increase with temperature or to exhibit a minimum. Comparison with available data favors the monotonic behavior and suggests directions for future measurements.