INTEGRAL RATE-CONSTANT MEASUREMENTS OF THE REACTION H+D2O-]HD(V',J')+OD

The reaction H + D2O was studied by intersecting a pulsed beam of HI with an effusive spray of D2O in a high vacuum chamber. Translationally hot H atoms were generated by UV photolysis of HI in the intersection volume, and the HD product of the reaction H + D2O was detected in a quantum-state-specific manner by (2+1) resonance-enhanced multiphoton ionization. Because the same UV laser beam was used to initiate the reaction and detect the product, the relative collision energy varied as a function of product state detected- approximately 2.8 eV for v'=0, approximately 2.6 eV for v'=1, and approximately 2.5 eV for v'=2. Under these conditions, approximately 35% of the available energy is partitioned into the internal modes of the HD product. For the products, the HD ''new bond'' receives 15 times more energy than the OD ''old bond.'' A significant amount of energy appears as HD vibration with v'=0 and 1 having comparable populations. The fraction of available energy partitioned into HD rotation, g(R)(v'), is found to be essentially independent of HD vibration. This invariance may be rationalized in terms of a counterbalancing of two mechanisms for rotational excitation of the HD product. We find qualitative agreement between recent quasiclassical trajectory calculations by Kudla and Schatz for the HD product internal-state distributions and the present experimental results.