Product-State-Resolved Dynamics Of The Elementary Reaction Of Atomic Oxygen With Molecular Hydrogen, O(P-3) + D-2 -> Od(X-2 Pi) + D

Elementary three-atom systems provide stringent tests of the accuracy of ab initio theory. One such important reaction, O(P-3) + H-2 -> OH(X-2 Pi) + H, has eluded detailed experimental study because of its high activation barrier. In this reaction, both the ground-state reactant atom and product diatomic molecule have open-shell character, which introduces the intriguing complication of non-Born-Oppenheimer effects in both the entrance and the exit channels. These effects may be probed experimentally in both the fine-structure and the Lambda-doublet splittings of the OH product. We have used laser-induced fluorescence to measure OD internal product-state distributions from the analogous reaction of O(P-3) with D-2, enabled by a unique high-energy O(P-3) source. We find that the OD (nu' = 0) product is rotationally highly excited, in excellent agreement with earlier theoretical predictions. However, the distributions over the OD(X-2 Pi) fine-structure and Lambda-doublet states, diagnostic of electronic non-adiabaticity in the reaction, challenge the prevailing theoretical understanding.