Competing Pathways in the Infrared Multiphoton Dissociation of Hexafluoropropene

Abstract

The infrared multiphoton dissociation of hexafluoropropene was studied by photofragment translational spectroscopy. Two primary channels and one secondary channel were identified. The predominant primary channel produces CF3CF or C2F4 and CF2, with the heavier species undergoing further dissociation to two CF2 fragments. A number of dissociation mechanisms are proposed for the elimination of CF2, including direct cleavage of the carbon−carbon double bond. In the second primary channel, a simple bond rupture reaction produces CF3 and C2F3. As expected, the translational energy distribution for this channel peaks near zero, indicating no exit barrier is present. The activation energy for this simple bond rupture is estimated to be 100−105 kcal/mol. The branching ratio, [CF2]/[CF3], between the two primary pathways is 4.0 ± 1.0.