Ultraviolet CO Chemiluminescence in CH(X2II) and CH(a4sigma-) Reactions with Atomic Oxygen at 298 K
ENGINEERING RESEARCH AND CONSULTING INC(ERC INC) EDWARDS AFB CA
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Production of ultraviolet CO chemiluminescence has been observed for the first time in the gas-phase pulsed laser photolysis of a trace amount of CEBr3 vapor in an excess of O-atoms. O-atoms were produced by dissociation of O2 or N2O in 4 cw-microwave discharge cavity in 2.0 torr Heat 298 K. Temporal profiles of the excited state products that formed in the photo-produced precursor O-atom or O2 reaction were measured by recording their time-resolved chemiluminescence in discrete vibronic bands. The CO. 4th Positive transition A1 II, vO - x1sigma, v2 near 165.7 nm, the CO Cameron band transition a3H, vO X1, v1 near 215.8 nm and the OH band transition A2, vl X211, vO near 282.2 nm were monitored in this work to deduce the decay kinetics of the chemiluminescence in the presence of various added substrates. From this the second-order rate coefficient values were determined for reactions of these substrates with the photo-produced precursors. Measured reactivity trends suggest that the prominent precursors responsible for the chemiluminescence are the methyfidyne radicals, CHX2H and CHa4-, whose production requires the absorption of at least 2 laser photons by the photolysis mixture. The 9-atom reactions with brominated precursors, which also form in the photolysis, are shown to play a minor role in the production of. the CO cherniluminescence. However, the CBr2 0-atom reaction was identified as a significant source for the ultraviolet Br2 chemilurninescence that was also observed in this work.
- Inorganic Chemistry
- Ultraviolet Detection and Detectors