Crossed molecular beams and quasiclassical trajectory studies of the reaction O(D-1)+H-2(D-2)

The dynamics of the reactions O(1D)+H2->OH+H and O(1D)+D2->OD+D have been investigated in crossed molecular beam experiments with mass spectrometric detection at the collision energies of 1.9 and 3.0 kcal/mol, and 5.3 kcal/mol, respectively. From OH(OD) product laboratory angular and velocity distribution measurements, center-of-mass product translational energy and angular distributions were derived. The angular distributions are nearly backward- forward symmetric with a favored backward peaking which increases with collision energy. About 30% of the total available energy is found to be channeled into product translational energy. The results are compared with quasiclassical trajectory calculations on a DIM ~diatomic-in-molecules! potential energy surface. Related experimental and theoretical works are noted. Insertion via the 1 1A8 ground state potential energy surface is the predominant mechanism, but the role of a second competitive abstraction micromechanism which should evolve on one of ~or both! the first two excited surfaces 1A9 and 2 1A8 is called into play at all the investigated energies to account for the discrepancy between theoretical predictions and experimental results.