The radical photodissociation channel of acrylonitrile

We have measured nascent Doppler profiles of CN (X2Σ+) fragments from the 193 nm photodissociation of acrylontrile using transient frequency-modulation spectroscopy. The Doppler profiles exhibit no μ · v or v · j correlations, and are consistent with the CN velocity distributions expected for a statistical, ground state dissociation. About 12% of the CN fragments have a single quantum of vibrational excitation, greater than the statistical prior prediction. However, the overall pattern of energy disposal and vector correlations is more consistent with a ground state, statistical fragmentation than a prompt, excited state dissociation. The CN quantum yield is 0.003 ± 0.001 at 193 nm.