Low Temperature Rate Constants for the Reactions of O(1D) with N2, O2, and Ar

The kinetics of the gas-phase quenching reactions O(D-1) + N-2, O(D-1) + O-2, and O(D-1) + Ar have been studied over the 50-296 K temperature range using the Laval nozzle method. O(D-1) atoms were created in situ by the pulsed photolysis of O-3 precursor molecules at 266 nm. Rate constants for these processes were measured directly, following the decay of O(D-1) atoms through vacuum ultraviolet laser-induced fluorescence at 115.215 nm. For the O(D-1) + N-2 and O(D-1) + O-2 reactions, the quenching efficiencies are seen to increase as the temperature falls. For the O(D-1) + N-2 system, this indicates the likely influence of the intermediate complex lifetime on the quenching rate through nonadiabatic processes. For the O(D-1) + O-2 system, which is considerably more complex, this behavior could result from the interactions between several potential energy surfaces.