State-to-state dissociation of OClO(Ã 2A2ν1,0,0)→ClO(X 2ΠΩ,v, J)+O(3P)

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Abstract
Applying the two-photon laser-induced fluorescence technique for nascent state resolved ClO(X 2ΠΩ,v,J) detection, the photofragmentation dynamics of OClO in the (Ã 2A211,0,0) and the (Ã 2A218,0,0) state is investigated at fixed photolysis wavelengths of 351 nm and 308 nm. In both experiments the product fragments are formed in their electronic ground states, namely ClO(2ΠΩ) and O(3P). A complete product state analysis proves the ClO radicals originating from the OClO(Ã 2A211,0,0) dissociation at 351 nm to be formed in v=0–4 vibrational states with a spin–orbit ratio of P(2Π3/2):P(2Π1/2)=3.8±0.5. The ClO fragment shows moderate rotational excitation. The obtained ClO product state distributions and the relatively high translational energy of the fragments can be explained by predissociation of the (Ã 2A2ν1,0,0)-excited parent molecule in the course of which the initial symmetric stretch motion (ν1) of OClO is transferred into the dissociative asymmetric stretching mode (ν3). ClO line profile measurements indicate a dissociation time of less than 0.5 ps. Resulting from the OClO(Ã 2A218,0,0) dissociation at 308 nm ClO is generated in very high vibrational states. The rotational excitation is comparable to that of the 351 nm photolysis study.