Rate coefficients and cross-sections for the reactions of C(3PJ) atoms with methylacetylene and allene

The reactivity of C(3PJ) atoms towards methylacetylene and allene has been investigated using complementary experimental methods. Kinetic measurements performed over the range T=15–295 K have yielded thermal rate coefficients: (2.7±0.6)×10−10(T/298 K)−(0.11±0.07) and (3.5±0.8)×10−10(T/298 K)−(0.01±0.12) cm3 molecule−1 s−1, respectively. Crossed beam experiments conducted in the range of relative translational energies εtr=4.9–282 meV have yielded integral cross-sections for H(2S1/2) production that are proportional to (εtr)−0.56±0.02 and (εtr)−0.55±0.01, respectively, in excellent agreement with the temperature dependencies of the rate coefficients.