Vibrationally Excited OD Radicals from the Reaction of Oxygen Atoms with Chemisorbed Deuterium on Tungsten

The possibility of producing highly excited OD radicals in the reaction of gas-phase atomic oxygen with deuterium chemisorbed on a tungsten surface has been explored using classical trajectory procedures. The many-body nature of the gas−surface reaction is explicitly considered in constructing a potential energy surface. Nearly all reactive events occur in a direct collision on a subpicosecond scale. The vibrational population distribution of OD radicals is found to be inverted, with the highest population appearing at vibrational level 6. The Eley−Rideal mechanism can account for these results. The calculations are carried out at the gas and surface temperatures of 1000 and 300 K, respectively, where the probability of OD formation is 0.12.