A rigorous test of the statistical model for atom-diatom insertion reactions

The statistical model of atom-diatom insertion reactions is combined with coupled-channel capture theory and used to calculate differential cross sections for the reactions of C(D-1), N(D-2), O(D-1) and S(D-1) with H-2. In the case of C(D-1) and S(D-1), the resulting statistical differential cross sections are found to be in excellent agreement with the recent quantum reactive scattering calculations of Honvault and Launay. They are therefore also in good agreement with molecular beam experiments for the S(D-1)+H-2 reaction, in contrast to the results of earlier calculations based on a less rigorous statistical theory. However, because the exact quantum mechanical differential cross sections for N(D-2) and O(D-1) exhibit a slight forward-backward asymmetry, the agreement with the statistical model for these reactions is not quite so good. The difference between the two cases can be rationalized in terms of the greater exoergicities of the N(D-2) and O(D-1) reactions, which lead to broader resonances and hence to shorter lifetimes of the H2O and NH2 collision complexes than those of CH2 and H2S. (C) 2003 American Institute of Physics.