Dissociation of ozonide in water

The free energy of bond dissociation for ozonide ion radical is found to be lowered in aqueous solution by about 20 kcal/mol relative to that in the g as phase, based on electronic structure calculations. Explicit treatment of anion-water clusters indicates that the stronger hydrogen bonds to first-s hell water molecules formed by O- relative to O-3(-) account for much of th e lowering. Reaction field methods show that nonspecific electrostatic pola rization of the bulk solvent further contributes noticeably to the lowering . The study clearly demonstrates that the aqueous free energy of ozonide bo nd dissociation is small, and probably endothermic. Our best semitheoretica l prediction of the actual value is 5 +/- 5 kcal/mol.