Electronic Polarizability and the Effective Pair Potentials of Water.
Employing the continuum dielectric model for electronic polarizability, we have developed a new consistent procedure for parameterization of the effective nonpolarizable potential of liquid water. The model explains the striking difference between the value of water dipole momentμ~3D reported in recentab initioand experimental studies with the valueμeff~2.3D typically used in the empirical potentials, such as TIP3P or SPC/E. It is shown that the consistency of the parameterization scheme can be achieved if the magnitude of the effective dipole of water is understood as a scaled value [Formula: see text], whereεel=1.78 is the electronic (high-frequency) dielectric constant of water, and a new electronic polarization energy term, missing in the previous theories, is included. The new term is evaluated by using Kirkwood - Onsager theory. The new scheme is fully consistent with experimental data on enthalpy of vaporization, density, diffusion coefficient, and static dielectric constant. The new theoretical framework provides important insights into the nature of the effective parameters, which is crucial when the computational models of liquid water are used for simulations in different environments, such as proteins, or for interaction with solutes.
Department of Chemistry, University of California Davis, One Shields Avenue, Davis, California 95616.
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Leontyev
Department of Chemistry, University of California Davis, One Shields Avenue, Davis, California 95616.
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Stuchebrukhov