The state distribution of OH radicals photodissociated from H2O2 at 193 and 248 nm

Abstract

Photodissociation of H₂O₂ at 248 and 193 nm yields largely vibrationless OH radicals in their ground electronic state. At 248 nm, on the average about 64 and 3 kcal/mol of energy are relased as translational and rotational energy, respectively. At 193 nm the corresponding quantities are 92 and 8 kcal/mol. The distribution of the OH radicals over K″ peaks near K″=5 when dissociated at 248 nm and near K″=6 at 193 nm but the latter distribution is somewhat broader. Doppler width anisotropy data imply that at 248 nm a single upper state is reached but that at 193 nm several upper surfaces may be responsible for the absorption. It is concluded that the upper state potential functions(s) may be respresented by the sum of a large repulsive term depending only upon the distance between centers of mass of the OH radicals and a small angularly dependent term which generates the rotational excitation.