REACTION FIELD EFFECTS ON THE SIMULATED PROPERTIES OF LIQUID WATER

The effects of including a reaction field contribution on the structur e and dynamics of liquid water have been investigated using molecular dynamics simulations. Reaction field effects are determined for two mo dels of water, the simple point charge (SPC) model and the extended si mple point charge (SPC/E) model, and at two temperatures (277 K and 30 0 K). Inclusion of the reaction field leads to a reduced system densit y, an increase in translational diffusion, which is model dependent, a n increase in internal energy, and an increase in rotational diffusion rates, in addition to the large (known) changes in the dielectric pro perties of liquid water. It is concluded that continued use of the rea ction field technique should involve a reparameterization of the water model and not merely a merging with the original model parameters.