Structure of the photochemical reaction path populated via promotion of CF₂i₂ into its first excited state

The photochemical reaction path following the promotion of CF ₂I₂ into its lowest-lying excited electronic singlet state has been modeled using ab initio multiconfigurational quantum chemical calculations. It is found that a conical intersection drives the electronically excited CF₂I₂* species either to the CF₂I + I radical pair or back to the starting CF₂I₂ structure. The structures of the computed relaxation pathways explain the photoproduct selectivity previously observed in the gas phase. Furthermore, the results provide the basis for explaining the condensed-phase photochemistry of CF ₂I₂.