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) x 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 HOx production/O(3) destruction within the marine boundary layer are briefly discussed.