The highly exoergic nucleophilic substitution reaction F–+ CH3I shows reaction dynamics
strikingly different from that of substitution reactions of larger halogen anions. Over a wide
range of collision energies, a large fraction of indirect scattering via a long-lived hydrogen-
bonded complex is found both in crossed-beam imaging experiments and in direct chemical
dynamics simulations. Our measured differential scattering cross sections show large-angle
scattering and low product velocities for all collision energies, resulting from efficient transfer …