The p h o t d i t i o n of C l s O (C, symmetry) at 248 and 193 nm has been studied by photofragment translational spectroscopy under various scattering angles. At 248 nm the decay proceeds along the molecular channel to SO + C12 but mainly along the fast (<10-l2 s) radical channel yielding C1+ SOCl. The anisotropy parameters show that the molecular and the radical decays arise from initial preparation of two states with A' and A" symmetry, respectively. At 193 nm the molecular and the radical processes are strongly dominated by a threebody dissociation (>8Wo) producing SO + C1+ CI. The photofragment anisotropies are consistent with the three competing, subpicosecond dissociation reactions starting on a single potential energy surface accessed via an A" -A' singlet transition. Furthermore, the fragment kinetic energy distribution of the radical channel at 248 and 193 nm indicates that SOCl has an excited electronic state at -9000 cm-I.

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The photodissociation dynamics of difluorodiiodomethane CF2I2 following 248 nm excitation were studied using the time-of-flight crossed laser-molecular beam technique. There is clear evidence that CF2I2 undergoes exclusively a simultaneous three-body dissociation. Two different reaction channels are observed: the dominant one (86%) yields CF2+I(2P1/2)+I(2P3/2) while the less efficient one (14%) produces the same fragments but in the ground state CF2+I(2P3/2)+I(2P3/2). The angle I–C–I between the recoil velocity vectors of the two departing I atoms was determined to be 120 °. The measured anisotropy parameters of βCF2=−0.8 for the CF2 fragments and βI=+1.1 for the I atoms (in both reaction channels) imply that the excited state symmetry of CF2I*2 is B1 (molecular symmetry C2v) and also indicate that the excited state lifetime is significantly shorter than a rotational period. Furthermore, the dissociation energy for the rupture of both C–I bonds was determined to be D0≤53 kcal/mol. Based on this dissociation energy a heat of formation for CF2I2 of ΔH0f, 0 K=−46 kcal/mol was calculated.

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