Effects of Rotational, Vibrational, and Translational Energy on the Rate Constants for the Isotope Exchange Reactions of OH(-) + Dsub2 and OD(-) + Hsub2
PHILLIPS LAB HANSCOM AFB MA
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Rate constants for the isotope exchange reactions of OH- with D sub 2 and OD- with H sub 2 have been measured as a function of average center-of- mass kinetic energy at several temperatures. The reaction of OH- with D sub 2 is slightly exothermic, and the rate constant has a negative temperature dependence. The kinetic energy dependences of the rate constants have minima near 0.1 eV. A strong negative dependence on the D sub 2 rotational temperature was found. The reason for this dependence is unclear at present. In contrast, the reaction of OD- with H sub 2 is slightly endothermic and shows positive dependences on both temperature and kinetic energy. The negative rotational dependence for the reaction of OD- with H sub 2 is not as large as that for OH- D sub 2, presumably because rotational energy can help overcome the endothermicity in the case of OD- H sub 2. Vibrational energy is observed to promote reactivity in both reactions.
- Physical Chemistry
- Atomic and Molecular Physics and Spectroscopy