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.