High-temperature reaction of C-2 with no including product channel measurements

The reaction of C-2 radicals with NO was studied behind reflected shock wav es in the temperature range 3150 K less than or equal to T less than or equ al to 3950 K. The shock-induced pyrolysis of acetylene, highly diluted in a rgon, was used as a well defined source for C-2 radicals, which were detect ed by ring-dye-laser absorption spectroscopy (RDLAS) at 516.646 nm. The per turbation of the C-2 by the addition of NO to the initial mixtures results in a fast removal of the C-2 radicals, which is mainly caused by the reacti on: C-2 + NO -->(k5) products for which the overall rate coefficient k(5)= 7.5 x 10(13) X exp(-4350/T)cm(3)mol(-1)s(-1) was obtained. The product channels of this reaction were studied by additio nal measurements of O-atoms. N-atoms, and CN radicals. O and N were detecte d using atomic resonance absorption spectroscopy (ARAS) and the CN radicals were followed by their emission using a spectrograph and an intensified CC D-camera. The reactions leading to the product channels C2N + O (R5a) and t o C2O + N (R5b) were identified as the main channels with a branching ratio of k(5a)/k(5) = 70% and k(5b)/k(5) = 30%, while the channel leading to CN + CO (R5c) was found to be neglectable. (C) 1999 John Wiley & Sons, Inc.