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Time-dependent quantum mechanical calculations on H + O$_2$ for total angular momentum $J > 0$ III: Total Cross Sections

Evelyn M. Goldfield

Dept. of Chemistry, Wayne State University, Detroit MI, 48202

Anthony J. H. M. Meijer

Dept. of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom

October 5, 2000


The H + O$_2$ $\longrightarrow$ OH + O reaction has been studied with a time-dependent wave packet method for total angular momentum $J = 15,
20,25,35$. This work is a continuation of previous studies for $J \leq
10$. The calculations were performed combining a real wave packet method with the Coriolis coupled method on parallel computers. We find that for most energies there is a monotonic decrease of reaction probability with increasing $J$. Nevertheless, due to the $2J+1$ degeneracy, higher angular momentum states contribute significantly to the total reaction cross section. A smoothing/interpolation/extrapolation scheme is employed to compute total reaction cross sections. These cross sections are compared with quasiclassical results on the same potential energy surface, and the most recent experimental cross sections. Comparisons with quasiclassical results show the significance of zero-point energy constraints. The quantum mechanical theoretical cross sections are everywhere smaller than the experimental ones, suggesting that a more accurate potential energy surface is required. There is also some possibility that nonadiabatic effects play a role in this reaction.

J. Chem. Phys. accepted, scheduled for 22 December issue.

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Next: Introduction
Anthony J. H. M. Meijer 2000-10-05