Saueressig, G.Bergamaschi, P.Crowley, J.Fischer, H.Harris, G.W.2010-06-102010-06-101995Geophy. Res. Letts., 22, 1225-1228http://hdl.handle.net/10315/4169The carbon kinetic isotope effect in the reaction between Cl and CH4 (KIECl) has been measured using tunable diode laser absorption spectroscopy to determine 13CH4/12CH4 ratios. Cl atoms were generated by the irradition of Cl2 in static mixtures of Cl2/CH4/N2 or Cl2/CH4/N2/O2. Both methods resulted in a (KIECl) of 1.066±0.002 at 297 K. The KIECl displayed a slight temperature dependence, increasing to 1.075±0.005 at 223 K. This result suggests a significant influence of the title reaction on the stratospheric CH4 isotopic composition and may help to resolve discrepancies between measurements of stratospheric 13CH4/ 12CH4 profiles and laboratory measurements of KIEOH.enArticlehttp://www.agu.org/journals/jd/