A laser flash photolysis-resonance fluorescence technique has been employed to determine absolute rate coefficients for the CH3F + Cl reaction in N2 bath gas in the temperature range of 200-700 K and pressure range of 33-133 hPa. The data were fitted to a modified Arrhenius expression k(T) ) 1.14 × 10-12 × (T/ 298)2.26 exp{-313/T}. The OH and Cl reaction rates of 13CH3F and CD3F have been measured by long-path FTIR spectroscopy relative to CH3F at 298 ( 2 K and 1013 ( 10 hPa in purified air. The FTIR spectra were fitted using a nonlinear least-squares spectral fitting method including line data from the HITRAN database and measured infrared spectra as references. The relative reaction rates defined by R ) klight/kheavy were determined to be kOH+CH3F/kOH+CD3F ) 4.067 ( 0.018, kOH+CH3F/kOH+13CH3F ) 1.067 ( 0.006, kCl+CH3F/kCl+CD3F ) 5.11 ( 0.07, and kCl+CH3F/kCl+13CH3F ) 1.016 ( 0.006. The carbon-13 and deuterium kinetic isotope effects in the OH and Cl reactions of CH3F have been further investigated by quantum chemistry methods and variational transition state theory.
Experimental and Theoretical Study of the Carbon-13 and Deuterium Kinetic Isotope Effects in the Cl and OH Reactions of CH3F
Marinkovic, M., M. Gruber-Stadler, J.M. Nicovich, R. Soller, M. Mülhäuser, P. Wine, L. Bache-Andreassen, and C.J. Nielsen (2008), Experimental and Theoretical Study of the Carbon-13 and Deuterium Kinetic Isotope Effects in the Cl and OH Reactions of CH3F, J. Phys. Chem. A, 112, 12416-12429, doi:10.1021/jp807609d.
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Upper Atmosphere Research Program (UARP)