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

Abstract

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.