Kinetics of the cross‐reaction of CH₃O₂ + HO₂ radicals measured in the Highly Instrumented Reactor for Atmospheric Chemistry

The sensitive Fluorescence Assay by Gas Expansion (FAGE) method has been used to detect methyl peroxy (CH3O2) and hydroperoxyl (HO2) radicals after their conversion titration with excess NO methoxy (CH3O) hydroxyl (OH) radicals, respectively, study the kinetics of reaction CH3O2 + HO2 radicals. rate coefficient was measured in Highly Instrumented Reactor for Atmospheric Chemistry (HIRAC) at 1000 mbar synthetic air T = 268–344 K, selectively detecting both Using a numerical model fit radical temporal decays globally each temperature investigated, coefficients have obtained. room found be kCH3O2 +HO2(295 K) (4.6 ± 0.7) × 10−12 molecule−1 cm3 s−1 (2σ errors) dependence can characterized Arrhenius form HO2(268 K < 344 (5.1 2.1) 10−13 exp((637 121)/T) s−1. obtained here are 14%–16% lower than literature recommended values an uncertainty which is reduced significantly compared previous reports.