Reaction of HOD+ with NO2: Effects of OD and OH stretching, bending, and collision energy on reactions on the singlet and triplet potential surfaces

Integral cross sections and product recoil velo-city distributions were measured for the reaction of HOD+ with NO2, in which the HOD+ reactant was prepared in its ground state and with mode-selective excitation in the 001 (OH stretch), 100 (OD stretch), and 010 (bend) modes. In addition, we measured the 300 K thermal kinetics in a selected ion flow tube reactor and report product branching ratios different from previous measurements. Reaction is found to occur on both the singlet and triplet surfaces with near-unit efficiency. At 300 K, the product branching indicates that triplet → singlet transitions occur in about 60% of triplet-coupled collisions, which we attribute to long interaction times mediated by complexes on the triplet surface. Because the collision times are much shorter in the beam experiments, the product distributions show no signs of such transitions. The dominant product on the singlet surface is charge transfer. Reactions on the triplet surface lead to NO+, NO2H+, and NO2D+. There is a...