Polarizable model of water with field-dependent polarization

The polarizable charge-on-spring model of water with three Gaussian charges developed by the present authors [A. Baranyai and P. T. Kiss, J. Chem. Phys. 133, 144109 (2010)] was studied. We introduced an analytic function for the polarizability in terms of the local electric field. Following theoretical suggestions, the polarizability decreases from its experimental gas-phase value, in our approach, toward a high-field threshold. Using this modified polarizability, we reparameterized the model by calculating its dielectric constant and obtained good estimates of density and internal energy for ambient water, hexagonal ice, and water cluster properties. Mimicked by the new model, we studied liquid water under the impact of homogeneous static electric field in the rage of 0-2.5 V/angstrom. Both the density and the average dipole moment increase with the strength of the electric field. However, the internal energy shows a minimum at similar to 0.35 V/angstrom. At this field strength, the model starts ordering into a crystal structure. At higher fields the liquid forms a crystalline structure which is a special version of cubic ice. (C) 2011 American Institute of Physics. [doi:10.1063/1.3670962]