Production of singlet oxygen atoms by photodissociation of oxywater

Quantum chemical calculations are reported for the energies of the few lowest electronic singlet states of oxywater along dissociation of the oxygen-oxygen bond into water and singlet oxygen using multistate multireference second-order Moller-Plesset perturbation theory. We compute an energy of 21 kcal/mol to remove one oxygen atom in the lowest singlet state. The two lowest excited singlet states have vertical excitation energies of 2.64 and 2.96 eV (470 and 419 nm) and are leading to the dissociation of the molecule. The two charge transfer states are accessible at vertical excitation of 4.91 and 5.22 eV (253 and 238 nm).