In this article we present the first calculations for higher total angular momentum states ( ) of the H + O reaction that treat Coriolis coupling rigorously. We show that, as expected, high states contribute significantly to the reaction cross section. Using smoothing/interpolation/extrapolation scheme we compute total reaction cross sections. We show that our cross sections are not influenced significantly by the exact parameters of this smoothing/interpolation/extrapolation scheme. These calculations are computationally intensive and are made possible through a combination of the efficient real wave packet scheme of Gray and Balint-Kurti, and the Coriolis-coupled parallel method of Goldfield and Gray.
We compare our cross sections with quasiclassical results of Varandas that make corrections for ZPE constraints and show that rather stringent corrections must be made to classical dynamics in order to achieve accurate results. We also compare with the most recent experimental cross sections.[17,50] The experimental cross sections are higher than the theoretical cross sections at all energies. Two possible explanations are (i) the DMBE IV PES is not accurate enough to product reliable cross sections and (ii) that nonadiabatic effects must be taken into account.
The H + O reaction displays a surprising amount of complexity for such a ``simple'' chemical reaction. It is important to include more of this complexity in future studies, including the development of more accurate PES's for the low-lying electronic states and the inclusion of nonadiabatic effects in dynamics calculations. While a full treatment of this reaction may be computationally daunting at present, further development of both algorithms and computer power ought to render such calculations feasible in the not-too-distant future.