The electronic properties of water molecules in water clusters and liquid water

A novel, self-consistent approach, applicable both for ground and excited e lectronic states, is introduced to calculate molecular properties in cluste rs and liquids. Using the method, carried out here at the second-order Moll er-Plesset perturbation theory (MP2) level, we obtain an average dipole mom ent of 2.65 D for water in liquid. Significant changes in quadrupole moment and polarizability, due to surrounding molecules, are also found along the water plane in the direction perpendicular to the axis bisecting the H-O-H bond angle. (C) 2000 Elsevier Science B.V.