Experimental and Computational Studies on the Reactivity of Methanimine Radical Cation (H<sub>2</sub>CNH<SUP>+•</SUP>) and its Isomer Aminomethylene (HCNH<sub>2</sub><SUP>+•</SUP>) With C<sub>2</sub>H<sub>2</sub>



Richardson, Vincent ORCID: 0000-0003-4766-0914, Ascenzi, Daniela, Sundelin, David, Alcaraz, Christian, Romanzin, Claire, Thissen, Roland, Guillemin, Jean-Claude, Polasek, Miroslav, Tosi, Paolo, Zabka, Jan
et al (show 1 more authors) (2021) Experimental and Computational Studies on the Reactivity of Methanimine Radical Cation (H<sub>2</sub>CNH<SUP>+•</SUP>) and its Isomer Aminomethylene (HCNH<sub>2</sub><SUP>+•</SUP>) With C<sub>2</sub>H<sub>2</sub>. FRONTIERS IN ASTRONOMY AND SPACE SCIENCES, 8.

Access the full-text of this item by clicking on the Open Access link.

Abstract

<jats:p>Experimental and theoretical studies are presented on the reactivity of the radical cation isomers H<jats:sub>2</jats:sub>CNH<jats:sup>+•</jats:sup> (methanimine) and HCNH<jats:sub>2</jats:sub><jats:sup>+•</jats:sup> (aminomethylene) with ethyne (C<jats:sub>2</jats:sub>H<jats:sub>2</jats:sub>). Selective isomer generation is performed via dissociative photoionization of suitable neutral precursors as well as via direct photoionization of methanimine. Reactive cross sections (in absolute scales) and product branching ratios are measured as a function of photon and collision energies. Differences between isomers’ reactivity are discussed in light of <jats:italic>ab-initio</jats:italic> calculations of reaction mechanisms. The major channels, for both isomers, are due to H atom elimination from covalently bound adducts to give [C<jats:sub>3</jats:sub>NH<jats:sub>4</jats:sub>]<jats:sup>+</jats:sup>. Theoretical calculations show that while for the reaction of HCNH<jats:sub>2</jats:sub><jats:sup>+•</jats:sup> with acetylene any of the three lowest energy [C<jats:sub>3</jats:sub>NH<jats:sub>4</jats:sub>]<jats:sup>+</jats:sup> isomers can form via barrierless and exothermic pathways, for the H<jats:sub>2</jats:sub>CNH<jats:sup>+•</jats:sup> reagent the only barrierless pathway is the one leading to the production of protonated vinyl cyanide (CH<jats:sub>2</jats:sub>CHCNH<jats:sup>+</jats:sup>), a prototypical branched nitrile species that has been proposed as a likely intermediate in star forming regions and in the atmosphere of Titan. The astrochemical implications of the results are briefly addressed.</jats:p>

Item Type: Article
Uncontrolled Keywords: methylene imine, acrylonitrile, vinyl cyanide, rate constant, cross sections, Titan, ISM, ion-molecule reactions
Depositing User: Symplectic Admin
Date Deposited: 07 Oct 2022 15:20
Last Modified: 17 Oct 2023 09:07
DOI: 10.3389/fspas.2021.752376
Open Access URL: http://doi.org/10.3389/fspas.2021.752376
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3165262