Reactions Forming Electronically-excited Free Radicals
Part 1. Ground-state reactions involving NF2 and NF radicals
Atomic resonance absorption in the far vacuum ultraviolet and atomic resonance fluorescence have been used to investigate the kinetics of primary and secondary processes in the overall reaction of H 2S atoms with NF2 radicals from 298 to 550 K. Rate constants for the following elementary reactions have been determined directly [k298/cm 3 molecule-1 s-1 (1 σ)]: H + NF 2 →k1 HF + NF; k1 = (1.5 ± 0.2) × 10-11; O + NF2 →k5 NF + FO; k 5 = (1.8 ± 0.9) × 10-12; N + NF2 →k8 NF + NF; k8 = (3.0 ± 1.2) × 10 -12. The overall H + NF2 reactive system, containing H2, is characterised as a self-propagating chain reaction, in which the chain carriers are H, NF and F. Ground-state N 4S atoms are formed by the reaction H + NF, although these atoms play only a minor role in propagating the overall H + NF2 chain reaction. Computer modelling of the H and N atom profiles was used to obtain values for k4 and k2: H + NF →k4 HF + N; k4 = (2.5 ± 0.5) × 10-13; NF + NF →k2 N2 + 2F; k2 = (7.0 ± 3.5) × 10-11. Thus, the predominant decay channel for NF radicals is through rapid bimolecular disproportionation to give N2 + 2F.
C. T. Cheah et al., "Reactions Forming Electronically-excited Free Radicals," Journal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics, Royal Society of Chemistry, Jan 1980.
The definitive version is available at http://dx.doi.org/10.1039/F29807600711
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© 1980 Royal Society of Chemistry, All rights reserved.