TRANSLATIONAL DISTRIBUTIONS OF FRAGMENTS PRODUCED IN THE PHOTODISSOCIATION OF VINYL FLUORIDE AT 157 NM

The photodissociation of vinyl fluoride following electronic excitatio n at 157 nm has been studied using the techniques of mass-resolved pho tofragment time-of-flight spectroscopy. HF elimination has been observ ed as the main primary dissociation process. This channel has a transl ational energy distribution peaked at around 20 kcal/mol, indicating t hat the reaction has a substantial exit barrier. We conclude that HF i s mainly produced via four-center elimination. Other primary reactions have also been observed and are tentatively assigned as the C-H bond rupture and H-2 elimination processes. The mechanisms of the unimolecu lar reactions of vinyl fluoride are discussed on the basis of ab initi o molecular orbital calculations.