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

The reactivity of C(P-3(J)) atoms towards methylacetylene and allene has be en investigated using complementary experimental methods. Kinetic measureme nts performed over the range T= 15-295 It have yielded thermal rate coeffic ients: (2.7 +/- 0.6) x 10(-10)(T/298 K)(-(0.11+/-0.07)) and (3.5 +/- 0.8) x 10(-10)(T/298 K)(-(0.01+/-0.12)) cm(3) molecule(-1) s(-1), respectively. C rossed beam experiments conducted in the range of relative translational en ergies epsilon (tr) = 4.9-282 meV have yielded integral cross-sections for H(S-2(1/2)) production that are proportional to (E-tr)(-0.56+/-0.02) and (e psilon (tr))(-0.55+/-0.01) respectively, in excellent agreement with the te mperature dependencies of the rate coefficients. (C) 2000 Elsevier Science B.V. All rights reserved.