Photodissociation of SO3 at 193 nm investigated by photofragment translational spectroscopy

We have generated a cold beam of the highly corrosive sulfur trioxide SO3 and have studied its photodissociation at 193 nm by photofragment translational spectroscopy. The spin-allowed process SO3(X̃1A′1) + hv → SO2(X̃1A1) + O(1D) was found to be the primary dissociation channel. A part of the hot SO2 fragments emerging from this decay undergoes secondary photodissociation SO2(X̃1A1) + hv → SO(X̃3∑−) + O(3P). No evidence was found for the occurrence of the energetically feasible pathway SO3(X̃1A′1) + hv → SO(3∑−) + O2(3∑g−).