Crossed beam study of the atom-radical reaction of ground state carbon atoms (C(3P)) with the vinyl radical (C2H3(X2A′))

The atom-radical reaction of ground state carbon atoms (C(3P)) with the vinyl radical (C2H3(X2A′)) was conducted under single collision conditions at a collision energy of 32.3 ± 2.9 kJ mol−1. The reaction dynamics were found to involve a complex forming reaction mechanism, which is initiated by the barrier-less addition of atomic carbon to the carbon–carbon-double bond of the vinyl radical forming a cyclic C3H3 radical intermediate. The latter has a lifetime of at least 1.5 times its rotational period and decomposes via a tight exit transition state located about 45 kJ mol−1 above the separated products through atomic hydrogen loss to the cyclopropenylidene isomer (c-C3H2) as detected toward cold molecular clouds and in star forming regions.