Dissociative recombination of C3H4+: preferential formation of the C3H3 radical

Branching ratios and absolute cross sections have been measured for the dissociative recombination of C3H4+ using the CRYRING ion storage ring. The pre-eminent channel involves the production of C3H3 and H, whereas processes involving rupture of carbon-carbon bonds are clearly disfavoured. The cross section of the reaction could be fitted to the expression [sigma] = 5.5 +/- 0.2 × 10-15 E-1.01 +/- 0.02, which leads to a thermal reaction rate of k(T) = 2.95 +/- 0.1 × 10-6 (T/300)-0.67 +/- 0.02 cm3 s-1.