The Dissociative Recombination of Protonated Acrylonitrile, CH2CHCNH+, with Implications for the Nitrile Chemistry in Dark Molecular Clouds and the Upper Atmosphere of Titan

• Published in: The Astrophysical journal 2009-04, Vol.695 (1), p.317-324
• Main Authors: Vigren, E, Hamberg, M, Zhaunerchyk, V, Kamińska, M, Thomas, R. D, Larsson, M, Millar, T. J, Walsh, C, Geppert, W. D
• Format: Article
• Language: English
• Subjects: Astronomy; Atom- och molekylfysik; Atomic and molecular physics; Chemical physics; Earth, ocean, space; Exact sciences and technology; Fysik; ISM: clouds; ISM: molecules; Kemisk fysik; methods: laboratory; molecular processes; NATURAL SCIENCES; NATURVETENSKAP; Physics
• ISSN: 0004-637X; 1538-4357; 1538-4357
• DOI: 10.1088/0004-637X/695/1/317

Measurements on the dissociative recombination (DR) of protonated acrylonitrile, CH2CHCNH+, have been performed at the heavy ion storage ring CRYRING located in the Manne Siegbahn Laboratory in Stockholm, Sweden. It has been found that at ~2 meV relative kinetic energy about 50% of the DR events involve only ruptures of X-H bonds (where X = C or N) while the rest leads to the production of a pair of fragments each containing two heavy atoms (alongside H and/or H2). The absolute DR cross section has been investigated for relative kinetic energies ranging from ~1 meV to 1 eV. The thermal rate coefficient has been determined to follow the expression k(T) = 1.78 X 10-6 (T/300) - 0.80 cm3 s-1 for electron temperatures ranging from ~10 to 1000 K. Gas-phase models of the nitrile chemistry in the dark molecular cloud TMC-1 have been run and results are compared with observations. Also, implications of the present results for the nitrile chemistry of Titan's upper atmosphere are discussed.