THE RADICAL PHOTODISSOCIATION CHANNEL OF ACRYLONITRILE

We have measured nascent Doppler profiles of CN (X(2) Sigma(+)) fragme nts from the 193 nm photodissociation of acrylonitrile using transient frequency-modulation spectroscopy. The Doppler profiles exhibit no mu . nu or nu . j correlations, and are consistent with the CN velocity distributions expected for a statistical, ground state dissociation. A bout 12% of the CN fragments have a single quantum of vibrational exci tation, greater than the statistical prior prediction. However, the ov erall pattern of energy disposal and vector correlations is more consi stent with a ground state, statistical fragmentation than a prompt, ex cited state dissociation. The CN quantum yield is 0.003 +/- 0.001 at 1 93 nm.