DYNAMICS OF 3-BODY HALF COLLISIONS .2. INSTANTANEOUS 3-BODY DECOMPOSITION IN THE PHOTO-DISSOCIATION OF TRIFLUOROACETYL IODIDE

Photofragment spectroscopy of trifluoroacetyl iodide (CF3COI) at 266 nm shows evidence of an instantaneous decomposition to I, CO, and CF 3 fragments. The transition dipole moment for photon absorption lies in the C-C-O plane within 20° of the C-I bond axis, and decomposition of the photoexcited CF3COI molecule is rapid (∼10-13 sec). A two-step dissociation model developed to explain acetyl iodide photodissociation does not apply to trifluoroacetyl iodide, indicating fluorine substitution has a dramatic effect on photodissociation dynamics. Monte Carlo trajectory calculations using a very simple potential energy surface are surprisingly successful in predicting the observed dissociation behavior. © 1979 American Institute of Physics.