Statistical treatment of recoil energy and angular distributions in the products of the reactions O(1D, 3P)+ICH3→OI+CH3

Recently, good agreement was found between experimental and phase space theory (PST) results concerning the recoil energy and angular distributions in the products of the reactions O(D-1, P-3) + ICH3 --> OI + CH3. The details of the calculations are presented in this work. Three models are proposed which assume different degrees of intramolecular vibrational redistribution (IVR) for the intermediate complex OICH3. It turns out that the reaction O(D-1) + ICH3 --> OI + CH3 might proceed through an osculating complex with a sufficiently short lifetime to excite only the vibrational modes of the complex which correlate with the stretching mode of OI and the umbrella mode of CH3. Conversely, reaction O(P-3) + ICH3 --> OI + CH3 proceeds via intersystem crossing between triplet and singlet surfaces through a long lifetime intermediate leading to an isotropic angular distribution of the products. Nevertheless, in opposition to the reaction O(D-1) + ICH3 --> OI + CH3, it appears difficult in this case to deduce the efficiency of the IVR process from the results obtained.