3CH2 + O2: Kinetics and Product Channel Branching Ratios

Abstract

Abstract The kinetics of and the yield of OH in the reaction 3CH2 + O2 has been studied at room temperature using pulsed laser photolysis of ketene at 351 nm with detection of OH by LIF. The kinetics were determined from a biexponential analysis of the growth and decay of the OH signal. The rate coefficients obtained from the profiles for OH(v=0,1) are (2.39 ± 0.26) and (2.33 ± 0.28) × 1012 cm3 molecule−1 s−1 respectively. The rate coefficient for 3CH2 + NO was also measured from the growth of the OH(v=1) signal, giving k 3 = (4.52 ± 0.48) × 1011 cm3 molecule−1 s−1. The ratio of the yields of OH in the two reactions 3CH2+O2 and 3CH 2+NO was determined from analysis of back to back OH profiles with O2 and NO as co-reactant; the ratio obtained, at 300 K, was 2.96 ± 0.14. This result was combined with other experimental product yields on these two reactions to obtain a consistent set channel yields for 3CH2+O2 and 3CH2+NO at ∼300 K.