Cavity ring-down spectroscopy and relative rate study of reactions of HCO radicals with O2, NO, NO2, and Cl2 at 295 K

Yuki Ninomiya, Masashi Goto, Satoshi Hashimoto, Yoshihisa Kagawa, Kazunari Yoshizawa, Masahiro Kawasaki, Timothy J. Wallington, Michael D. Hurley

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32 Citations (Scopus)


Cavity ring-down absorption spectroscopy was used to measure k(HCO + O2) = (5.9 ± 0.5) × 10-12, k(HCO + NO) = (1.9 ± 0.2) × 10-11, and k(HCO + Cl2) = (7.6 ± 0.7) × 10-12 cm3 molecule-1 s-1 in 4-10 Torr of N2 diluent at 295 K. FTIR/smog-chamber techniques were used to measure the following rate constant ratios in 15-750 Torr of N2 diluent at 295K: k(HCO + O2)/k(HCO + Cl2) = 0.85 ± 0.02, k(HCO + NO)/k(HCO + Cl2) = 2.80 ± 0.10, and k(HCO + NO2)/k(HCO + Cl2) = 8.45 ± 0.38. Consistent results were obtained from the two different techniques. In 15-700 Torr of N2 diluent at 295 K the reaction of HCO with Cl2 proceeds via a single channel giving HC(O)Cl + Cl, reaction of HCO with NO gives CO in a yield indistinguishable from 100%, and reaction of HCO with NO2 gives a 70% yield of CO and a 30% yield of CO2. Ab initio calculations show that the reaction of HCO radicals with Cl2 proceeds via the formation of the HC(O)Cl2 complex, which decomposes, rapidly to HC(O)Cl and a Cl atom.

Original languageEnglish
Pages (from-to)7556-7564
Number of pages9
JournalJournal of Physical Chemistry A
Issue number32
Publication statusPublished - Aug 2000
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry


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