PHOTOFRAGMENTATION OF THIONYL CHLORIDE - COMPETITION BETWEEN RADICAL, MOLECULAR, AND 3-BODY DISSOCIATIONS

The photodissociation of Cl2SO (C(s) 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 + Cl2 but mainly along the fast (< 10(-12) s) radical channel yielding Cl + 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 three-body dissociation (> 80%) producing SO + Cl + Cl. 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 approximately 9000 cm-1.