INCORPORATING ELECTRIC POLARIZABILITIES IN WATER WATER INTERACTION POTENTIALS

Water-water interaction potentials that include many-body corrections through classical electric polarizabilities and the corresponding induced dipoles are investigated. Significant attention is given to the transferability of gas-phase dimer potentials to condensed phases. The potential functions used are parametrized by using information about the gas-phase dimer potential surface from ab initio CI calculations (the raw data used for the parametrization of the MCY model, modified for its incorrect behavior at long distances). The potential thus obtained is examined and tuned by extensive calculations of the crystal structures and lattice energies of proton-ordered polymorphs of ice (ices II, IX, and VIII). These crystal calculations involve a novel energy-minimization procedure for the treatment of the induced dipoles and their energy contributions. Some of the popular water-water potentials (MCY, TIPS2, and SPC) are also examined for comparison. Our potentials reproduce fairly well experimental crystal structures and lattice energies, demonstrating that the transferability problems suffered by pairwise-additive potentials such as the MCY model can be removed by explicitly including polarizabilities and induced dipoles. © 1990 American Chemical Society.