REACTION OF O-2(-2, D-2, AND HD - GUIDED ION-BEAM STUDIES, MO CORRELATIONS, AND STATISTICAL-THEORY CALCULATIONS()(X (2)PI(G)) WITH H)

Absolute cross sections are measured for the reactions of 02+ (X2PI(g) ) with H-2, D2, and HD from thermal energies to over 4 eV. The OH+ + O H, HO2+ + H, 0+ + H2O, and H2O+ + O product channels (and the correspo nding isotopic analogs) are observed, although H-2+ + O2 is not. While the first three products appear at their thermodynamic thresholds, fo rmation of H2O+ + O, the least endothermic channel, exhibits a barrier to reaction. In the HD system, the DO2+ product ion is strongly favor ed over the HO2+ product. Results for internally excited O2+ reactants , probably the a 4PI(u) state, are also presented. Analysis of the exc itation functions, molecular orbital arguments, and statistical kineti c theories are used to understand the mechanisms and dynamics of this reaction. It is shown that the inefficiency of the 0-product channel i s due to spin and symmetry constraints. The other three product channe ls proceed through a long-lived intermediate, but formation of this in termediate from reactants requires surmounting a barrier measured to b e 1. 1 +/- 0.1 eV. The intramolecular isotope effects are shown to be due to statistical and dynamic effects.