Investigating the chemical dynamics of the reaction of ground-state carbon atoms with acetylene and its isotopomers

We investigated the multichannel reaction of ground-state carbon atoms with acetylene, C2H2 (X-1 Sigma(+)(g)), to form the linear and cyclic C3H isomers (atomic hydrogen elimination pathway) as well as tricarbon plus molecular hydrogen. The experiments were conducted under single-collision conditions at three different collision energies between 8.0 kJ mol(-1) and 31.0 kJ mol(-1). Our studies were complemented by crossed molecular beam experiments of carbon with three isotopomers C2D2(X-1 Sigma(+)(g)), C2HD (X-1 Sigma(+)), and (C2H2)-C-13 (X-1 Sigma(+)(g)) to clarify a potential intersystem crossing (ISC), the effect of the symmetry of the reaction intermediates on the center-of-mass angular distributions, the collision energy-dependent branching ratios of the atomic versus molecular hydrogen elimination pathways, and deuterium-enrichment processes. The results are discussed in light of recent electronic structure and dynamics calculations.