Completely inverted ClO vibrational distribution from OClO(2A2 24,0,0)

The gas phase dissociation dynamics of symmetric chlorine dioxide highly photoexcited into its (2)A(2) 24,0,0 vibronic level has been investigated by monitoring both the kinetic energy release and the angular distribution of the O(P-3(2)) products via velocity map imaging. The resulting O(P-3(2)) kinetic energy profile provides full the vibrational distribution of the formed ClO(X (2)Pi,upsilon) radicals. The measured O fragment kinetic energy distribution reflects an unprecedented nonstatistical vibrational state population of their diatomic partners, where the excess energy is focused only in the three highest possible ClO vibrational levels upsilon = 18-20, with little fragment rotation. The anisotropy of the dissociation process sheds new light on the fragmentation dynamics of this stratospherically relevant triatomic molecule. (C) 2000 American Institute of Physics. [S0021-9606(00)00112-4].