The viscosity of the Price–Brooks modified TIP3P water model is investigated for different temperatures and NaCl concentrations using molecular dynamics with long-range electrostatic interactions. The viscosity has been determined from the equilibrium fluctuations of the pressure tensor by the Green–Kubo formalism. At 298 K in salt-free conditions, the resulting viscosity is higher than the value reported by other authors for TIP3P water. The viscosity is shown to decrease with temperature and increase with salt concentration, such as in real water, but with an absolute value always about half of the experimental value in analogous conditions. This difference must be attributed to the simplicity and the empirical nature of the TIP3P model, and also to the properties chosen for the original parameterisation, which did not include viscosity. At the considered levels of salinity, the effect of temperature is predominant.
- molecular dynamics
- water model