Rate Coefficients for the Reaction of Iodine Oxide with Methyl Peroxy Radicals

Pulsed laser photolysis radical generation is used to study the title reaction IO+CH 3 O 2 →products. Sensitive and selective laser‐induced fluorescence detection of IO allows excess CH 3 O 2 conditions to be maintained throughout, ensuring minimal interference from other fast IO reactions. The rate coefficients, k 5 (296 K)=(3.4±1.4)×10 −12 cm 3  molecule −1  s −1 , are obtained relative to a well‐characterised reference value ( k 3 for IO+HO 2 ). This result agrees well with a previous determination from this laboratory and demonstrates that the above reaction proceeds an order of magnitude slower than suggested in other recent experimental and theoretical studies. Implications for HO x production/O 3 destruction within the marine boundary layer are briefly discussed.