H atom branching ratios from the reactions of CN radicals with C2H2 and C2H4

The room temperature branching ratios to H atom channels for the reactions of CN with C2H2 (1.08+/-0.13) and C2H4 (1.04+/-0.11) have been determined by observing the time resolved production of H atoms and comparing the H atom signal with that from a calibration reaction (CN+H-2 --> H+HCN). The kinetics of all three reactions have been determined by monitoring both CN decay and H atom growth and are in good agreement with most previous studies. (C) 2003 Elsevier B.V. All rights reserved.