title: A combined crossed molecular beam and theoretical investigation of the reaction of the meta-tolyl radical with vinylacetylene--toward the formation of methylnaphthalenes.
abstract: Crossed molecular beam experiments and electronic structure calculations on the reaction of the meta-tolyl radical with vinylacetylene were conducted to probe the formation of methyl-substituted naphthalene isomers. We present the compelling evidence that under single collision conditions 1- and 2-methylnaphthalene can be formed without an entrance barrier via indirect scattering dynamics through a bimolecular collision of two non-PAH reactants: the meta-tolyl radical and vinylacetylene. The electronic structure calculations, conducted at the UCCSD(T)-F12b/cc-pVDZ//UM06-2x/cc-pVTZ + ZPE(UM06-2x/cc-pVTZ) level of theory, reveal that this reaction is initiated by the barrierless addition of the meta-tolyl radical to the terminal vinyl carbon (C1) of vinylacetylene, via a van-der-Waals complex implying that this mechanism can play a key role in forming methyl-substituted PAHs in low temperature extreme environments such as the low temperature interstellar medium and hydrocarbon-rich atmospheres of planets and their moons in the outer solar system. The reaction mechanism, proposed from the C11H11 potential energy surface, involves a sequence of isomerizations involving hydrogen transfer and ring closure, followed by hydrogen dissociation, which eventually leads to 1- and 2-methylnaphthalene in an overall exoergic process.
authors.affiliation: Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA. ralfk@hawaii.edu.
authors.forename: Tao
authors.initials: T
authors.lastname: Yang
authors.forename: Lloyd
authors.initials: L
authors.lastname: Muzangwa
authors.forename: Ralf I
authors.initials: RI
authors.lastname: Kaiser
authors.forename: Adeel
authors.initials: A
authors.lastname: Jamal
authors.forename: Keiji
authors.initials: K
authors.lastname: Morokuma