On the formation of resonantly stabilized C5H3 radicals--a crossed beam and ab initio study of the reaction of ground state carbon atoms with vinylacetylene

Dorian S N Parker; Fangtong Zhang; Y Seol Kim; Ralf I Kaiser; Alexander M Mebel

doi:10.1021/jp109800h

On the formation of resonantly stabilized C5H3 radicals--a crossed beam and ab initio study of the reaction of ground state carbon atoms with vinylacetylene

J Phys Chem A. 2011 Feb 10;115(5):593-601. doi: 10.1021/jp109800h. Epub 2010 Dec 31.

Authors

Dorian S N Parker¹, Fangtong Zhang, Y Seol Kim, Ralf I Kaiser, Alexander M Mebel

Affiliation

¹ Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii, USA.

PMID: 21194192
DOI: 10.1021/jp109800h

Abstract

The formation of polycyclic aromatic hydrocarbons in combustion environments is linked to resonance stabilized free radicals. Here, we investigated the reaction dynamics of ground state carbon atoms, C((3)P(j)), with vinylacetylene at two collision energies of 18.8 kJ mol(-1) and 26.4 kJ mol(-1) employing the crossed molecular beam technique leading to two resonantly stabilized free radicals. The reaction was found to be governed by indirect scattering dynamics and to proceed without an entrance barrier through a long-lived collision complex to reach the products, n- and i-C(5)H(3) isomers via tight exit transition states. The reaction pathway taken is dependent on whether the carbon atom attacks the π electron density of the double or triple bond, both routes have been compared to the reactions of atomic carbon with ethylene and acetylene. Electronic structure/statistical theory calculations determined the product branching ratio to be 2:3 between the n- and i-C(5)H(3) isomers.