| Reported here are first-principles computation of rate constants for the atmospheric reactions OOH + ClO → HOCl + 1O2 and OOH + H → H2 + 3O2, by combining canononcial variational theory (CVT) and high-level electronic structure theory. Extending the direct dynamics approach, the rate constants were computed, directly, using ab initio electronic structure theory at the second-order many-body perturbation theory [MBPT(2)], complete active space self consistent field (CASSCF), and coupled-cluster singles-and-doubles with a perturbative triples correction [CCSD(2)] levels, and canonical variational theory including tunneling. The computed temperature dependent rate constants for OOH + ClO → HOCl + 1O2 fall well within the range of mutually discordant experiments. The computed room temperature rate constant of 6.79 × 10−12 cm3 molecule−1 s−1 for OOH + H → H2 + 3O2 is in excellent agreement with experiment (6.96 × 10−12). |
