Kinetics of CH Radicals With O2: Evidence for CO-Chemiluminescence in the Gas Phase Reaction.

摘要

Production of CO vis-uv-chemiluminescence has been observed for the first time in the gas phase reaction of photolytic-methylidyne radicals with molecular oxygen. A trace amount of CMBr3 vapor was photo-decomposed in a pulsed-photolysis reactor using a 248-nm laser under multi-photon-dissociation conditions to produce the CH(X(sup 2)H) radicals in an excess of O2 in diluent helium carrier gas at 2.0 torr and 298 K. The time resolved chemiluminescent traces due to characteristic CO(A-X), CO(a-X) and CO(d-a) vibronic emissions were recorded at several band positions. 147.8 nm was the shortest wavelength at which CO emission was recordable. The integrated intensities of the CO emissions showed a quadratic dependence on the photolysis fluence employed as did the OH(A-X) emission in the (1-0) band. The dependence of the OH and CO chemiluminescence on O2 was studied to obtain the rate coefficient(s) for the chemiluminescent reaction(s). The data is best interpreted by postulating that CM(v >- O) reactions with O2 lead to the observed CO-emissions as well as the well-known OH-chemiluminescence.