TY - JOUR
AU - Richardson, Vincent
AU - Ascenzi, Daniela
AU - Sundelin, David
AU - Alcaraz, Christian
AU - Romanzin, Claire
AU - Thissen, Roland
AU - Guillemin, Jean-Claude
AU - Polášek, Miroslav
AU - Tosi, Paolo
AU - Žabka, Jan
AU - Geppert, Wolf D.
PY - 2021
M3 - Original Research
TI - Experimental and Computational Studies on the Reactivity of Methanimine Radical Cation (H2CNH+•) and its Isomer Aminomethylene (HCNH2+•) With C2H2
JO - Frontiers in Astronomy and Space Sciences
UR - https://www.frontiersin.org/articles/10.3389/fspas.2021.752376
VL - 8
SN - 2296-987X
N2 - Experimental and theoretical studies are presented on the reactivity of the radical cation isomers H2CNH+• (methanimine) and HCNH2+• (aminomethylene) with ethyne (C2H2). 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 ab-initio calculations of reaction mechanisms. The major channels, for both isomers, are due to H atom elimination from covalently bound adducts to give [C3NH4]+. Theoretical calculations show that while for the reaction of HCNH2+• with acetylene any of the three lowest energy [C3NH4]+ isomers can form via barrierless and exothermic pathways, for the H2CNH+• reagent the only barrierless pathway is the one leading to the production of protonated vinyl cyanide (CH2CHCNH+), 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.
ER -