Kinetics of CN reactions with O(3P) and SO2

The rate constant for CN+O was measured using SO2 and N2O as O precursors. 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 quenching 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) × 1013 cm3mol−1s−1 and for CN + SO2k2 = (2.65 ± 0.15) × 1012 cm3mol−1s−1.