Photodissociation spectroscopy and dynamics of the CH2CFO radical

The photodissociation spectroscopy and dynamics resulting from excitation of the B ˜ 2A9ÃX ˜ 2A9 transition of CH2CFO have been examined using fast beam photofragment translational spectroscopy. The photofragment yield spectrum reveals vibrationally resolved structure between 29 870 and 38 800 cm21, extending;6000 cm21 higher in energy than previously reported in a laser-induced fluorescence excitation spectrum. At all photon energies investigated, only the CH2F1CO and HCCO1HF fragment channels are observed. Both product channels yield photofragment translational energy distributions that are characteristic of a decay mechanism with a barrier to dissociation. Using the barrier impulsive model, it is shown that fragmentation to CH2F1CO products occurs on the ground state potential energy surface with the isomerization barrier between CH2CFO and CH2FCO governing the observed translational energy distributions