Hydrogen exchange reaction H + D2 in crossed beams

Despite its fundamental importance as the prototypical bimolecular reaction, the hydrogen exchange reaction still remains a challenging and open problem, both experimentally and theoretically. Theory has now developed to a stage much superior to that of experiment. Nowhere is this more true than, for example, in the determination of differential scattering cross-sections, state-to-state specific with respect to the vibrational and rotational degrees of freedom of the molecular products. In this paper we describe a new experimental approach to such measurements, and present first results from crossed-beam studies of the H + D2 reaction (at relative translational energies of 1.29 and 0.54 eV) using the novel technique of hydrogen Rydberg atom time-of-flight spectroscopy to monitor the velocity and angular distributions of the D atom product.