Vibrational-rotational energy distributions in the reaction O- + D2 --> OD + D-

The D(+) transfer reaction between O(-) ((2)P) and D(2) to form OD and D(-) was studied using the crossed molecular beam technique at collision energies of 1.55 and 1.95 eV. The reaction appears to proceed by a direct mechanism through large impact parameters. At both collision energies, more that 70% of the excess energy is partitioned into product translation. At the lower collision energy, the OD products are formed in the ground vibrational state with a bimodal rotational energy distribution. At the higher collision energy, both v' = 0 and 1 products are formed; ground vibrational state products have a mean rotational energy of 0.05 eV, corresponding to J' approximately 6. In contrast, OD products formed in v' = 1 are formed with significant rotational excitation, with the most probable J' approximately 15. The bimodal rotational distribution is rationalized in terms of trajectories that sample two potential surfaces coupled by a conical intersection in the vicinity of the [O...DD](-) intermediate that correlate to (OD(-),D) or (OD,D(-)) products.