Dynamic and structural behavior of different rigid nonpolarizable models of water

The local structure and the dynamical behavior of water have been analyzed in two different regimes (the dense isochore of 0.995 g/cm(2) and the supercritical isotherm of 673 K) through four rigid nonpolarizable models of water. An important change in the slope of temperature dependence of the self-diffusion coefficient at rho=0.995 has been observed at Tapproximate to450 K, showing two main regions that are related to a change on the activation energy of the process (originated for a change of the structure of the first solvation shell from a tetrahedral to dodecahedral arrangement). The local orientational structure of water has been analyzed through the use of tetrahedral order parameters q. A direct relation between q and D has been observed for all models showing some kind of master curve up to 450 K at the 0.995 g/cm(3) isochore. The structure of the system at short and large radial distances has been analyzed through a decomposition of the site-site radial distribution functions in terms of spherical harmonics, and a three-dimensional picture of the total pair distribution function has been reconstructed from this set of spherical harmonic projections. (C) 2003 American Institute of Physics.