A theoretical study of unimolecular reactions of vinyl fluoride. Potential surface characteristics and their mechanistic implications

A b inito MO calculations have been performed for potential energy surfaces of unimolecular reactions of vinyl fluoride. The geometries and energies of the reactant, transition states, reaction intermediates, and product have been determined for ten elementary reactions both on the triplet and the singlet surfaces. The mechanism of the unimolecular dissociation reaction has been discussed in terms of the energy diagram obtained by the present calculation and compared with the interpretation derived from photosensitizer and IR-multiphoton experiments. We have also calculated the intrinsic reaction coordinate (IRC) for the αα- and αβ-HF direct elimination reactions and discussed the mechanism of energy partitioning in the reaction product. We propose an experiment that would determine which of the αα and αβ processes is dominant in the HF elimination reaction.