SIMBAD references

2020MNRAS.492.2140D - Mon. Not. R. Astron. Soc., 492, 2140-2150 (2020/February-3)

Low-temperature chemistry induced by cosmic rays: positive and negative ion desorption from nitrile-bearing astrophysical ice analogues.

DE RIBEIRO F.A., ALMEIDA G.C., WOLFF W., BOECHAT-ROBERTY H.M., ROCCO M.L.M. and DA SILVEIRA E.F.

Abstract (from CDS):

In cold core of dark molecular clouds, where the UV radiation from external sources is strongly attenuated, cosmic rays can induce chemical reactions on the surface of ice-covered grains promoting the ejection of the processed material to the gas phase. We report the positive and negative secondary ion emission from pure CH3CN, C2H3CN, and i-C3H7CN ices due to the bombardment of heavy ions (252Cf fission fragments), simulating the incidence of cosmic rays on to icy surfaces. The secondary ions emitted from each sample were analysed by time-of-flight mass spectrometry, using Plasma Desorption Mass Spectrometry technique. Several ionic species were identified, indicating strong fragmentation on the frozen surface. Proton-transfer processes are suggested to play a role for positive ion desorption, as evidenced by the protonated RCNH+ parent molecules and (RCN)nH+ ionic clusters. The high electron affinity of the cyano radical seems to contribute to the strong emission of CN, as well as anions attributed to the CHmCN fragment and (RCN)nCN cluster series. Sputtering and desorption of ion clusters (positive and negative) induced by heavy ion bombardment are suggested to constitute a route by which new neutral or ionized molecular species may be delivered to the gas phase where thermal desorption is negligible.

Abstract Copyright: © 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society

Journal keyword(s): astrochemistry - molecular processes - solid state: volatile - methods: laboratory: solid state - cosmic rays

Simbad objects: 9

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2021.06.25-09:08:02

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