Reaction Field Effects on the Simulated Properties of Liquid Water

Abstract

The effects of including a reaction field contribution on the structure and dynamics of liquid water have been investigated using molecular dynamics simulations. Reaction field effects are determined for two models of water, the simple point charge (SPC) model and the extended simple point charge (SPC/E) model, and at two temperatures (277 K and 300 K). Inclusion of the reaction field leads to a reduced system density, an increase in translational diffusion, which is model dependent, an increase in internal energy, and an increase in rotational diffusion rates, in addition to the large (known) changes in the dielectric properties of liquid water. It is concluded that continued use of the reaction field technique should involve a reparameterization of the water model and not merely a merging with the original model parameters.

Key Words:

• Reaction field
• Water
• SPC
• SPC/E