Nonequilibrium molecular dynamics calculation of the shear viscosity of liquid water

Abstract

The shear viscosity, pressure, and configurational (SPC) internal energy of liquid water at four densities along the 303.15 K isotherm are calculated using nonequilibrium molecular dynamics. The interaction between the water molecules is modeled by the SPC pair potential of Berendsen and co-workers. The simulation results are compared with experimental data at the same temperatures and densities. The shear viscosity is found to be approximately 50% lower than the experimental results but has a similar slope as a function of density. The results for the full SPC potential are compared to those of a model fluid whose pair potential is obtained by setting the electrostatic part of the SPC interaction to zero. The results for the shear viscosity are remarkably similar to those of SPC water, suggesting that the electrostatic interactions make a very small contribution to the viscosity for this fluid.