Potential energy characteristics and energy partitioning in chemical reactions: A b i n i t i o MO study of H2CCH2F→H2CCHF+H reaction

Geometries, relative energies, and normal coordinates for the reactant, the transition state (saddle point), and the product were determined for the unimolecular dissociation reaction H2CCH2F→H2C=CHF+H, by the use of the energy gradient technique in the ab initio SCF method with a split valence basis set. The saddle point is located near the dissociation product. The RRKM theory including a tunneling correction was used to calculate the average lifetime of the reactant complex. Nonstatistical internal and translational energy distributions observed experimentally in the reaction product were interpreted by the analysis of the potential energy characteristics: the deformation and interaction contributions to the reverse activation barrier and the relationship between the transition state normal coordinates and the product normal coordinates.