A discharge–flow study of the kinetics of the reactions of IO with CH3O2 and CF3O2

We have determined the rate constants for the reactions IO + CH3O2 --> Products (1) and IO + CF3O2 --> Products (2) using a discharge-flow tube equipped with off-axis cavity-enhanced absorption spectroscopy (CEAS) for the detection of IO. NO2, produced from the titration of RO2 with NO, was also detected using the CEAS system. The rate constants obtained were k1 = (6.0 +/- 1.3) x 10(-11) cm3 molecule(-1) s(-1) and k2 = (3.7 +/- 0.9) x 10(-11) cm3 molecule(-1) s(-1) at T = 295 +/- 2 K and P = 2.5 +/- 0.3 Torr; this is the first determination of these rate constants. The possible products and the atmospheric implications of reaction (1) are discussed.