Polarizability effects in a four-charge model for water

A planar four-charge model for the water molecule, with a spherically symmetric Lennard-Jones potential and a point polarizability, is examined. The model parameters are determined by fitting gas-phase data for the one and two-molecule systems. A reasonable description of water clusters of up to five molecules is obtained. The model gives qualitatively accurate properties in liquid and solid phases, but not enough condensation for agreement with experiment. It is suggested that the use of a point polarizability only partially accounts for many-body effects. Alternatives to the above model are discussed.