Reactive scattering of a supersonic methyl radical beam: CH3 + ICl, IBr, I2, Br2

Reactive scattering of CH3 radicals with ICl, IBr, I2 and Br2 molecules has been studied at an initial translational energy E ∼ 30kJ mol-1, using a supersonic beam of CH3 radicals seeded in He buffer gas. Laboratory angular and velocity distributions of CH3I and CH3Br product have been measured which show a gradation from short-lived complex dynamics for ICl to rebound dynamics for I2 and Br2 with intermediate behaviour for IBr. This variation in dynamics is attributed to the form of the potential energy surface which shifts from a shallow hollow for CH3 + ICl to repulsion in the exit valley for CH3 + I2, Br2, with both features being present for the intermediate case of CH3 + IBr.