SOLVENT POLARIZATION AND HYDRATION OF THE CHLORINE ANION

The effect of solvent polarization around a Cl- ion in water is investigated by molecular dynamics simulation. Two different solvent models that each take account of the collective polarization are compared to the popular TIP4P potential. The first is an effective pair potential which incorporates polarization in a mean-field approximation. The second is a polarizable model which treats the many-body induction as a separate dynamical degree of freedom for each molecule. The hydration number found in the TIP4P solvent is reduced in both polarization models. Although the ion-solvent radial distribution functions for the polarizable models are in reasonable agreement with neutron scattering data, the time scale of the solvent relaxation processes in both models is too slow. This finding is in marked contrast with the case of TIP4P, where the time scales for such processes are too fast. The enhanced rigidity of the polarization models is a consequence of the large self-polarization correction. © 1990 American Chemical Society.