Crossed-beam investigation of translational energy effects in oxygen atom reactions

The reactions of oxygen atoms with I2, CS2, and OCS have been investigated using crossed molecular beams, for two mean collision energies (∼5 and ∼30 kJ mol−1). The reaction O+I2→IO+I exhibits an unexpected change in behavior from long-lived complex formation at low energy to a backwards-scattering rebound mechanism at higher energy. Translational energy is very effective in overcoming the small activation barrier to the O+CS2→SO+CS reaction, but appears ineffective in promoting the analogous reaction O+OCS→SO+CO, which has a higher activation energy.