DYNAMICS CALCULATIONS AND ISOTOPIC EFFECT IN O-]O-2+H(D) AT LOW ENERGIES(OH(D))

The deuterium isotopic effect in the gas-phase reaction O(3P) + OH(2PI ) --> O2(X3SIGMA(g)-) + H(2S) has been studied in detail over the rang e of translational energies 0.125 less-than-or-equal-to E(tr)/kcal mol -1 less-than-or-equal-to 1.0, which correspond to the temperature rang e 40 less-than-or-equal-to T/K less-than-or-equal-to 340. State-to-sta te dynamics calculations covering the range of rotational quantum numb ers 0 less-than-or-equal-to j less-than-or-equal-to 14 have been carri ed out using both the quasi-classical internal energy quantum mechanic al threshold (QCT-IEQMT) and quasi-classical rotational and vibrationa l energy quantum mechanical threshold (QCT-NVEQMT) methods. The QCT-NV EQMT calculations show an inversion of population in the vibrational d istributions of the product O2 molecules, with v' = 1 being the most p opulated level. It is also found, by both the QCT-IEQMT and QCT-NVEQMT methods, that the initial rotational state of the reactant OH(D) mole cule plays an important role in determining non-statistical recrossing . All calculations used the double many-body expansion (DMBE IV) poten tial-energy surface for ground-state HO2. The magnitude of the isotopi c effect is shown to depend to some extent on the approach used for th e dynamics calculations. The contributions of the various terms to the thermal rate coefficient are also examined.