Gp. Knight et al., Reaction of HO2 with ClO: Flow tube studies of kinetics and product formation between 215 and 298 K, J PHYS CH A, 104(8), 2000, pp. 1674-1685
Rate coefficients for the reaction between HO2 and ClO radicals were obtain
ed using the discharge-flow/mass-spectrometry technique at total pressures
of 1.1-1.7 Torr of He, and between 298 and 215 K. The room-temperature rate
constant, determined using seven different combinations of HO2 and ClO pre
cursors, was found to be (7.1 +/- 1.8) x 10(-12)(+/-2 sigma) cm(3) s(-1). T
he temperature-dependent overall reaction rate coefficient is described by
k((3)) (298-215 K) = (7.1 +/- 0.4) x 10(-12) exp(-16 +/- 17/T) cm(3) s(-1).
The previous observation of a strong negative temperature dependence in th
e title reaction below 298 K was not observed, resulting in a significantly
lower rate coefficient at stratospheric temperatures. HOCl was the only pr
oduct of the reaction, and an upper limit of 1% for the branching ratio for
the formation of O-3 and HCl was obtained at the low pressures of these ex
periments.