Kinetics of the reactions of ClO with O and with NO

The rate constants k1, k2, and k3 for the reactions Cl + O3 yields ClO + O2 (1), ClO + O yields Cl + O2 (2), and ClO + NO yields Cl + NO2 (3), respectively, were measured by the discharge-flow technique, in which chlorine atoms are added to a flow of O3 and either O or NO in a helium carrier gas. The conditions of the experiment were such that the steady-state concentration ratios of Cl to ClO are simply interpretable in terms of the rate constant ratios k2/k3 or k3/k1. These rate constant ratios were measured over the range 220 to 298 K and combined with the directly determined k1 value to yield k2 and k3. The results are: k1 = 2.12 x 10 to the -11th exp(-157/T); k2 = 3.38 x 10 to -11th exp(75 plus or minus 40/T); and k3 = 1.13 x 10 to the -11th exp(200 plus or minus 30/T) cu cm/sec.