On the realism of the re-engineered simple point charge water model

The realism of the recently proposed high-temperature reparameterization of the simple point charge (SPC) water model [C. D. Berweger, W. F. van Gunsteren, and F. Muller-Plathe, Chem. Phys. Lett. 232, 429 (1995)] is tested by comparing the simulated microstructure and dielectric properties to the available experimental data. The test indicates that the new parameterization fails dramatically to describe the microstructural and dielectric properties of water at high temperature: it predicts rather strong short-range site-site pair correlations, even stronger than those for water at ambient conditions, and a threefold smaller dielectric constant. Moreover, the resulting microstructure suggests that the high-temperature force-field parameters would predict a twofold higher critical density. The failure of the high-temperature parameterization is analyzed and some suggestions on alternative choices of the target properties for the weak-coupling are discussed. (C) 1996 American Institute of Physics.