A time-resolved technique for measuring rates of alkyl radical-atom reactions: The pressure dependence of the CH 3 + H reaction at 504 K

Abstract

The rate constant for the CH 3 + H reaction has been measured as a function of pressure at 504 K. A new technique was employed, in which the temporal behaviour of both the atom and radical was measured, by resonance fluorescence and UV absorption spectroscopy respectively, following excimer laser flash photolysis of acetone at 193 nm. A minor complication, resulting from the production of small amounts of CH 2 from a two-photon process, was eliminated by studying the atom and radical decays as a function of laser pulse energy.