A shock tube study of the reactions of NH with NO, O 2 , and O

The reactions of NH(X 3 Σ − ) with NO, O 2 , and O have been studied in reflected and incident shock wave experiments. The source of NH in all the experiments was the thermal dissociation of isocyanic acid, HNCO. Time‐histories of the NH(X 3 Σ) and OH(X 2 Π) radicals were measured behind the shock waves using cw, narrow‐linewidth laser absorption at 336 nm and 307 nm, respectively. The second‐order rate coefficients of the reactions:were determined to be:\documentclass{article}\pagestyle{empty}\begin{document}$$ k_{\rm 3} \, = \,1.7 \times 10^{14} \exp (- 6400/{\rm T,K)}\,\,\,\,\,\,{\rm (}f\, = \,0.65,{\rm F}\,{\rm =}\,{\rm 1}{\rm .5)}\,\,\,\,\,\,{\rm T}\,{\rm =}\,{\rm 2220 - 3350\, K,} $$\end{document}\documentclass{article}\pagestyle{empty}\begin{document}$$ k_{\rm 4} \, = \,3.5 \times 10^{13} \exp (- 6800/{\rm T,K)}\,\,\,\,\,\,{\rm (}f\, = \,0.65,{\rm F}\,{\rm =}\,{\rm 1}{\rm .5)}\,\,\,\,\,\,{\rm T}\,{\rm =}\,{\rm 2220 - 3370\, K,} $$\end{document}and\documentclass{article}\pagestyle{empty}\begin{document}$$ k_{\rm 5} \, = \,9.2 \times 10^{13} \,\,\,\,\,\,\,\,\,\,\,\,{\rm (}f\, = \,0.60,{\rm F}\,{\rm =}\,{\rm 1}{\rm .6)}\,\,\,\,\,\,{\rm T}\,{\rm =}\,{\rm 2730 - 3380\, K,} $$\end{document}cm 3 mol −1 s −1 , where ƒ and F define the lower and upper uncertainty limits, respectively. The branching fraction of channeldefined as k 3b / k 3total , was determined to be 0.19 ± 0.10 over the temperature range of 2940 K to 3040 K.