Vapor–liquid equilibrium simulations of the SCPDP model of water

Molecular simulations were carried out using the self-consistent point dipole polarizability model (SCPDP) of water in the region of vapor–liquid equilibrium. The methods of isothermal–isochoric molecular dynamics (NVT–MD) and Gibbs ensemble Monte Carlo (GEMC) were employed to calculate orthobaric densities and vapor pressures; NVT–MD also yields surface tensions and interface thickness. Agreement was found between the two methods, particularly at lower temperatures, but compared with experimental results, this model over-predicts vapor pressures and densities, and under-predicts the liquid density, surface tension, and interface thickness. The interface thickness predicted by the SCPDP model showed better agreement with experimental results than a simpler extended point charge model (SPC/E).