title: Hydrogen-Abstraction/Acetylene-Addition Exposed.
abstract: Polycyclic aromatic hydrocarbons (PAHs) are omnipresent in the interstellar medium (ISM) and also in carbonaceous meteorites (CM) such as Murchison. However, the basic reaction routes leading to the formation of even the simplest PAH-naphthalene (C10H8)-via the hydrogen-abstraction/acetylene-addition (HACA) mechanism still remain ambiguous. Here, by revealing the uncharted fundamental chemistry of the styrenyl (C8H7) and the ortho-vinylphenyl radicals (C8H7)-key transient species of the HACA mechanism-with acetylene (C2H2), we provide the first solid experimental evidence on the facile formation of naphthalene in a simulated combustion environment validating the previously postulated HACA mechanism for these two radicals. This study highlights, at the molecular level spanning combustion and astrochemistry, the importance of the HACA mechanism to the formation of the prototype PAH naphthalene.
authors: Department of Chemistry, University of Hawai'i at Manoa, Honolulu, HI, 96822, USA.
authors: Tao
authors: 0000-0003-4101-2385
authors: T
authors: Yang
authors: Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
authors: Tyler P
authors: TP
authors: Troy
authors: Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
authors: Bo
authors: B
authors: Xu
authors: Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
authors: Oleg
authors: 0000-0003-2068-4991
authors: O
authors: Kostko
authors: Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
authors: Musahid
authors: M
authors: Ahmed
authors: Department of Chemistry and Biochemistry, Florida International University, Miami, FL, 33199, USA.
authors: Alexander M
authors: AM
authors: Mebel
authors: Department of Chemistry, University of Hawai'i at Manoa, Honolulu, HI, 96822, USA.
authors: Ralf I
authors: 0000-0002-7233-7206
authors: RI
authors: Kaiser
keywords: combustion; gas-phase chemistry; hydrogen-abstraction/acetylene-addition (HACA); mass spectrometry; polycyclic aromatic hydrocarbons