State-resolved predissociation dynamics of the formyloxyl radical

Dissociation dynamics of the deuterated formyloxyl radical, DCO2, were studied by photoelectron–photofragment coincidence spectroscopy of DCO 2 - . Photodetachment at 4.27 eV accesses the three lowest-lying electronic states (2A1, 2B2, and 2A2) of DCO2, leading to vibrational excitation dominated by the 2A1 state O−C−O bending mode. Predissociation leads to bending excitation in the CO2 products as observed in the product translational energy distribution. Gating the coincidence spectra by electron kinetic energy for each predissociated vibrational mode in the radical provides a direct measure of the CO2 bending vibration (ν2) product state distribution, revealing substantially more excitation than ab initio quantum-dynamics calculations predict.