2-aminooxazole In Astrophysical Environments: IR Spectra And Destruction Cross Sections For Energetic Processing


Unit cell of the computed structure of the 2-aminooxazoleO molecular crystal (blue dashed lines show the hydrogen bond network)

2-aminooxazole (2AO), a N-heterocyclic molecule, has been proposed as an intermediate in prebiotic syntheses. It has been demonstrated that it can be synthesized from small molecules such as cyanamide and glycoaldehyde, which are present in interstellar space.

The aim of this work is to provide infrared spectra, in the solid phase for conditions typical of astrophysical environments and to estimate its stability toward UV photons and cosmic rays. Infrared (4000-600 cm−1) absorption spectra at 20 K, 180 K, and 300 K, IR band strengths, and room temperature UV (120-250 nm) absorption spectra are given for the first time for this species. Destruction cross-sections of 9.5 10−18 cm2 and 2 10−16 cm2 were found in the irradiation at 20 K of pure 2AO and 2AO:H2O ices with UV (6.3-10.9 eV) photons or 5 keV electrons, respectively. These data were used for the estimate of half-life times for the molecule in different environments.

It is estimated that 2AO could survive UV radiation and cosmic rays in the ice mantles of dense clouds beyond cloud collapse. In contrast, it would be very unstable at the surface of cold Solar System bodies like Kuiper belt objects, but the molecule could still survive within dust grain agglomerates or cometesimals.

Belén Maté, Ricardo Carrasco-Herrera, Vicente Timón, Isabel Tanarro, Victor J. Herrero, Héctor Carrascosa, Guillermo M. Muñoz Caro, Cristóbal González-Díaz, Izaskun Jiménez-Serra

Comments: 31 pages, 9 figures. Accepted to be published in The Astrophysical Journal
Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Chemical Physics (physics.chem-ph)
Cite as: arXiv:2101.06164 [astro-ph.IM] (or arXiv:2101.06164v1 [astro-ph.IM] for this version)
Submission history
From: Belén Maté
[v1] Fri, 15 Jan 2021 15:17:48 UTC (1,300 KB)
Astrobiology, Astrochemistry,

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