KINETICS OF CN REACTIONS WITH O (P-3) AND SO2

The rate constant for CN + O was measured using SO2 and N2O as O precu rsors. For CN + SO2, CN was formed by 248 nm photolysis of BrCN where SO2 does not dissociate. For the O(3P) reaction 193 nm photolysis was used where SO2 yields O(3P) and SO and N2O yields O(3P) after rapid qu enching of the O(1D) by an excess of nitrogen. Rates were measured as a function of photolysis flux, with the O atom yield being determined by the number of absorbed photons. The rate constant for CN + O(3P) is k1 = (2.22 +/- 0.45) x 10(13) cm3 mol-1 s-1 and for CN + SO2 k2 = (2. 65 +/- 0.15) x 10(12) cm3 mol-1 s-1.