Theoretical investigation of reaction between amidogen NH & ethyl C2H5 radicals: possible gas-phase formation route of interstellar and planetary etha

Nadia Balucani, Dimitrios Skouteris, Cecilia Ceccarelli, Claudio Codella, Stefano Falcinelli, Marzio Rosi

(Submitted on 24 Oct 2018)

The reaction between the amidogen, NH, radical and the ethyl, C2H5, radical has been investigated by performing electronic structure calculations of the underlying doublet potential energy surface. Rate coefficients and product branching ratios have also been estimated by combining capture and RRKM calculations. According to our results, the reaction is very fast, close to the gas-kinetics limit. However, the main product channel, with a yield of ca. 86-88% in the range of temperatures investigated, is the one leading to methanimine and the methyl radical. The channels leading to the two E-, Z- stereoisomers of ethanimine account only for ca. 5-7% each. The resulting ratio [E-CH3CHNH]/[Z-CH3CHNH] is ca. 1.2, that is a value rather lower than that determined in the Green Bank Telescope PRIMOS radio astronomy survey spectra of Sagittarius B2 North (ca. 3). Considering that ice chemistry would produce essentially only the most stable isomer, a possible conclusion is that the observed [E-CH3CHNH]/[Z-CH3CHNH] ratio is compatible with a combination of gas-phase and grain chemistry. More observational and laboratory data are needed to definitely address this issue.

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Chemical Physics (physics.chem-ph)

Journal reference: Volume 13, November 2018, Pages 30-37

DOI: 10.1016/j.molap.2018.10.001

Cite as: arXiv:1810.10416 [astro-ph.EP] (or arXiv:1810.10416v1 [astro-ph.EP] for this version)

Submission history

From: Nadia Balucani  

[v1] Wed, 24 Oct 2018 14:23:36 UTC (869 KB)

https://arxiv.org/abs/1810.10416