Density and temperature effects on the orientational and dielectric properties of supercritical water

The influence of temperature and density changes on the reorientational motions and dielectric properties of supercritical water is investigated by molecular dynamics simulations. A rigid simple point charged potential has been used to model water-water interactions. This model has revealed to be very satisfactory to reproduce thermodynamic, diffusive, and static dielectric properties of supercritical water. Reorientation times of water molecules have been computed along specific molecular directions and compared with available experimental data. The imaginary part of the frequency dependent dielectric constant, spectral densities of states, and residence times of water molecules in their first hydration shells are also evaluated.