The exoergic F+CH4 reaction as an example of peripheral dynamics

Classical trajectory computations for thermal reactants on a six-atom potential show a forward scattering component which is correlated with the HF product being formed with high vibrational excitation. These trajectories are peripheral collisions where the F atom approaches CH4 with a high impact parameter and reaction is through a nearly collinear F–H–C configuration with a stretched F–H bond. Other trajectories are well described by a hard-sphere model whose cutoff is below the range of peripheral collisions. Comparison is made with the F+H2 and other reactions where nearly thermoneutral channels correlate with forward scattering.