Shock Tube Measurements of the Rate Constant of the Reaction NCN + O-2

Fassheber, Nancy and Friedrichs, Gernot (2015) Shock Tube Measurements of the Rate Constant of the Reaction NCN + O-2 International Journal of Chemical Kinetics, 47 (9). pp. 586-595.

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The rate constant of the comparably slow bimolecular NCN radical reaction NCN + O-2 has been measured for the first time under combustion relevant conditions using the shock tube method. The thermal decomposition of cyanogen azide (NCN3) served as a clean high-temperature source of NCN radicals. NCN concentration-time profiles have been detected by narrow-bandwidth laser absorption at 30383.11 cm(-1). The experiments behind incident shock waves have been performed with up to 17% O-2 in the reaction gas mixture. At such high O-2 mole fractions, it was necessary to take O-2 relaxation into account that caused a gradual decrease of the temperature during the experiment. Moreover, following fast decomposition of NCN3 and collision-induced intersystem crossing of the initially formed singlet NCN to its triplet ground state, an unexpected and slow additional formation of triplet NCN has been observed on a 100-s timescale. This delayed NCN formation was attributed to a fast recombination of (NCN)-N-1 with O-2 forming a (NCNOO)-N-3 adduct acting as a reservoir species for NCN. Rate constant data for the reaction NCN + O-2 have been measured at temperatures between 1674 and 2308 K. They are best represented by the Arrhenius expression . No pressure dependence has been observed at pressures between 216 and 706 mbar.

Document Type: Article
Additional Information: Times Cited: 2
Research affiliation: Kiel University
OceanRep > The Future Ocean - Cluster of Excellence
Refereed: Yes
ISSN: 0538-8066
Projects: Future Ocean
Date Deposited: 20 Oct 2016 10:53
Last Modified: 08 Feb 2018 11:46

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