Cryogenic Chemistry and Quantitative Non‐Thermal Desorption from Pure Methanol Ices: High‐Energy Electron versus X‐Ray Induced Processes

Torres-Díaz, Daniela; Basalgète, Romain; Bertin, M.; Fillion, J.-H.; Michaut, X.; Amiaud, L.; Lafosse, A.

doi:10.1002/cphc.202200912

Cited by 2 publications

(1 citation statement)

References 56 publications

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“…Nonthermal desorption mechanisms have been proposed and are being currently investigated to account for their presence in the gas phase. These mechanisms include electron promoted desorption (Marchione & McCoustra 2016), X ray induced desorption (Torres-Díaz et al 2023;Kalvāns 2021), desorption induced by exothermic reactions (Garrod et al 2007;Vasyunin & Herbst 2013) and, notably, UV photodesorption (Öberg et al 2009;Cruz-Diaz et al 2017) and cosmic ray (CR) sputtering (Dartois et al 2017(Dartois et al , 2022Pino et al 2019). Overall, COMs are expected to be highly diluted in the ice mantles of dust grains and on many occasions their gas-phase concentrations should thus be given by the desorption rate of the dominant ice molecules.…”

Section: Introductionmentioning

confidence: 99%

Indene energetic processing in ice mantles in the interstellar medium

Maté,

Tanarro,

Peláez

et al. 2024

A&A

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Indene, a small PAH, has been detected in the gas phase in the cold dense cloud TMC-1. Due to the low temperature in the cloud, below indene condensation temperature, its presence in the ice mantles of dust grains is likely. The aim of this work is to study the stability of indene against the energetic processing by VUV photons or cosmic rays in the ice mantles of dense molecular clouds. Ice layers of pure indene or indene diluted in water ice were grown by vapor deposition on a cold surface held at 10 K, 100 K, or 140 K. The samples were processed with VUV photons (120 -180 nm) and 5 keV electrons and the destruction of indene was monitored by following the decay of the its absorption bands in the infrared (IR) spectrum. Finally, we recorded the mass spectra of the decomposition products sublimated by thermal programmed desorption of the processed samples.. Photolysis and radiolysis cross-sections, along with half-life energy doses for indene in the solid a form and diluted in water ice matrices at 10 K were derived. Ketones and alcohols were identified as the main processing products in indene and water-ice mixtures Dilution in water ice enhances the destruction rate of indene under energetic processing. The molecule is expected to survive for more than 10$^7$ yr in the ice mantles of grains in the interior dense clouds, but it will end up getting destroyed within the next few hundred years by the intense VUV field in the diffuse region at the edges of the cloud.

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Section: Introductionmentioning

confidence: 99%

Indene energetic processing in ice mantles in the interstellar medium

Maté,

Tanarro,

Peláez

et al. 2024

A&A

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Astro-electrochemistry of NH3 clusters and ice: e− trapping, stability, and electron transfer

Fioroni,

Ramabhadran,

DeYonker

2024

Monthly Notices of the Royal Astronomical Society

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Quantifying electron trapping and transfer to small molecules is crucial for interfacial chemistry. In an astrochemical context, we study how NH3 clusters in both crystalline and amorphous forms can capture low-energy electrons to form ammoniated electrons. Electron affinities, vertical detachment energies, and vertical attachment energies were computed via ab initio static and dynamics simulations, (DFT, DLPNO-CCSD(T);AIMD), for (NH3)n clusters (n = 4, 5, 6, 8, 14, 23, and 38). Our results indicate that the clusters could trap and stabilize the unpaired electron which is always externally localized on the clusters. Interactions of the ammoniated electron clusters with astrochemically relevant molecules indicate that electron transfer to water and methanol are feasible, forming the radical anions (H2O)−· and (CH3OH)−·. The trapping of electrons by both crystalline and amorphous NH3 ices, and subsequent transfer to small molecules, highlights ‘astro-electrochemical’ reactions, and has implications for both astrochemistry as well as terrestrial cluster science.

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Cryogenic Chemistry and Quantitative Non‐Thermal Desorption from Pure Methanol Ices: High‐Energy Electron versus X‐Ray Induced Processes

Abstract: Supporting information for this article is given via a link at the end of the document.

Cited by 2 publications

References 56 publications

Indene energetic processing in ice mantles in the interstellar medium

Indene energetic processing in ice mantles in the interstellar medium

Astro-electrochemistry of NH3 clusters and ice: e− trapping, stability, and electron transfer

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