Monte Carlo simulation of RRKM unimolecular decomposition in molecular beam experiments. V. product ox angular and energy distributions from O( 3P)+X 2 (X = Br, I)

Abstract

Statistical simulation was applied to the unimolecular decomposition of the collision complexes formed in the crossed beam experiments on O( 3P) + Br 2 by Fernie et al. and O( 3P) + I 2 by Durkin et al. The simulation procedure used the fundamentals of RRKM theory and included exact angular momentum conservation. The impact parameter distributions were varied to obtain the best fits. Good agreement with experimental laboratory angular distributions measured with O atoms seeded in both He and Ne was found for impact parameter distributions which were peaked at quite small values, in most cases between 2 and 3 Å. Product OX molecules were found to be rotationally excited and inverted with a mean rotational energy close to twice the value expected without angular momentum restrictions. The differences found between the calculated and the experimental angular distributions do not support any assumptions about osculating or short-lived complexes. The normal exoergicity Δ D 0 of 27 kJ/mol for the O + I 2 reaction agrees well with the experiments by Dunkin et al.