3CH2 + O2: Kinetics and Product Channel Branching Ratios

The kinetics of and the yield of OH in the reaction (CH2)-C-3 + O-2 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(upsilon = 0, 1) are (2.39 +/- 0.26) and (2.33 +/- 0.28) x 10(-12) cm(3) molecule(-1) s(-1) respectively. The rate coefficient for (CH2)-C-3 + NO was also measured from the growth of the OH(upsilon = 1) signal, giving k(3) = (4.52 +/- 0.48) x 10(-11) cm(3) molecule(-1) s(-1). The ratio of the yields of OH in the two reactions (CH2)-C-3 + O-2 and (CH2)-C-3 + NO was determined from analysis of back-to-back OH profiles with O-2 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 (CH2)-C-3 + O-2 and (CH2)-C-3 + NO at similar to 300 K.