Radiolysis and sputtering of carbon dioxide ice induced by swift Ti, Ni, and Xe ions

Mejía, C.; Bender, Markus; Severin, D.; Trautmann, C.; Boduch, P.; Bordalo, V.; Domaracka, A.; Lv, X. Y.; Martínez, R.; Rothard, H.

doi:10.1016/j.nimb.2015.09.039

Cited by 34 publications

(30 citation statements)

References 27 publications

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“…In general, the measured and adjusted destruction cross sections for ices at low temperature show a power-law dependency with 1 < n < 1.5, for example, CH 3 OH, n = 1.1, this work; CO 2 (n = 1.1, Fig. 5, Mejía et al 2015) as a function of the electronic stopping power. As discussed in Dartois et al (2018), experiments and thermal spike models of the phase transformation induced by the ion track in insulators predict a dependency of the radius r of the cross section that evolves as r ∼ √ S e , where S e = dE/dx is the deposited energy per unit path length (e.g.…”

Section: Radiolytic Destruction Versus Sputtering Dependency As a Funmentioning

confidence: 62%

Non-thermal desorption of complex organic molecules

Dartois

Chabot

Barkach

et al. 2019

A&A

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Context. The occurrence of complex organic molecules (COMs) in the gas phase at low temperature in the dense phases of the interstellar medium suggests that a non-thermal desorption mechanism is at work because otherwise, COMs should condense within a short timescale onto dust grains. Vacuum ultraviolet (VUV) photodesorption has been shown to be much less efficient for complex organic molecules, such as methanol, because mostly photoproducts are ejected. The induced photolysis competes with photodesorption for large COMs, which considerably lowers the efficiency to desorb intact molecules. Aims. We pursue an experimental work that has already shown that water molecules, the dominant ice mantle species, can be efficiently sputtered by cosmic rays. We investigate the sputtering efficiency of complex organic molecules that are observed either in the ice mantles of interstellar dense clouds directly by infrared spectroscopy (CH3OH), or that are observed in the gas phase by millimeter telescopes (CH3COOCH3) and that could be released from interstellar grain surfaces. Methods. We irradiated ice films containing complex organic molecules (methanol and methyl acetate) and water with swift heavy ions in the electronic sputtering regime. We monitored the infrared spectra of the film as well as the species released to the gas phase with a mass spectrometer. Results. We demonstrate that when methanol or methyl acetate is embedded in a water-ice mantle exposed to cosmic rays, a large portion is sputtered as an intact molecule, with a sputtering yield close to that of the main water-ice matrix. This must be even more true for the case of more volatile ice matrices, such as those that are embedded in carbon monoxide. Conclusions. Cosmic rays penetrating deep into dense clouds provide an efficient mechanism to desorb complex organic molecules. Compared to the VUV photons, which are induced by the interaction of cosmic rays, a large portion desorb as intact molecules with a proportion corresponding to the time-dependent bulk composition of the ice mantle, the latter evolving with time as a function of fluence due to the radiolysis of the bulk.

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Section: Radiolytic Destruction Versus Sputtering Dependency As a Funmentioning

confidence: 62%

Non-thermal desorption of complex organic molecules

Dartois

Chabot

Barkach

et al. 2019

A&A

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“…The desortpion (or sputtering) induced by swift ions in ices is several orders of magnitude higher than the one produced by ionizing photons and can Processing of astrophysical ice analogs by soft X-rays and swift ions 283 reach values around 10000 molecules/impact (Brown et al 1984;Baragiola et al 2003;Pilling et al 2010a), and as discussed by Rocha et al (2017), may be also dependent on ice polarity (ices composed of polar molecules are more resistant to destruction, whereas apolar molecule-containing ices are more easily destroyed). Additionally, it has been observed that the number of molecules ejected after ion impact scale with the square of the electronic projectile energy loss (Seperuelo-Duarte et al 2010;Dartois et al 2015;Mejía et al 2015).…”

Section: Introductionmentioning

confidence: 99%

Processing of astrophysical ices by soft X-rays and swift ions

Pilling

2017

Proc. IAU

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The employment of soft X-rays and swift ions has been used in laboratory to simulate the physicochemical processing of astrophysical ice analogs by energetic photons and cosmic rays. This processing includes excitation, ionization and molecular dissociation, desorption, as well as triggers the formation of new compounds. Here we present some results from experiments employing infrared spectroscopy in two different laboratories: LNLS/CNPEM in Campinas/Brazil and GANIL/CIRIL/CIMAP in Caen/France. Among the results are the formation of alkenes and aromatic compounds during the irradiation of saturated hydrocarbon-containing ices by cosmic ray analogs, the production of the nucleobase adenine during soft X-ray photolysis of N2:CH4 ice, as well as the formation of peptide bonds during the bombardment of frozen glycine by cosmic ray analogs. The interaction between cosmic ray analogs and ionizing soft X-rays probed in the laboratory allows us to identify reaction routes that lead to chemistry enhancement of astrophysical ices and help us put constrains in prebiotic chemistry.

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“…As discussed above, the first points at low fluence, below about 10 11 ions cm −2 were discarded from our fit, as they do not follow the theoretical expected −dN/dF behaviour. Mejía et al (2015) reported a strong decrease of the sputtering yield for thin CO 2 films exposed to 132 Xe 21+ ions at 630 MeV. Using the adjusted expected experimental yields for semi-infinite thick films, extrapolated to the stopping power of this experiment (S e = 5680 eV/10 15 CO 2 molecules cm −2 ), a crude estimate of the sputtering depth can be made.…”

Section: Radiolysis Sputtering Yield and Depth Determinationmentioning

confidence: 93%

“…The projectiles used were 40 Ca 9+ at 38.4 MeV and 58 Ni 9+ at 33 MeV with an electronic stopping power, calculated using the SRIM package (Ziegler et al 2010) for CO 2 ice of S e = 1919.1 eV/10 15 CO 2 molecules cm −2 and S e = 2487.8 eV/10 15 CO 2 molecules cm −2 , respectively. We also made use of additional experiments already presented in Seperuelo Duarte et al (2009) for C 18 O 2 using a 46 MeV 58 Ni 11+ projectile, a measurement on a CO 2 very thin film irradiated with a 630 MeV 132 Xe 21+ presented in Mejía et al (2015), and a low-energy 100 keV proton irradiation experiment on CO 2 from Raut & Baragiola (2013). For CO ice with projectiles of 40 Ca 9+ at 38.4 MeV, the S e = 1245.2 eV/10 15 CO molecules cm −2 , and for 58 Ni 9+ at 33 MeV, the S e = 1613.2 eV/10 15 CO molecules cm −2 .…”

Section: Methodsmentioning

confidence: 99%

“…Bron et al 2014) and sputtering in the electronic interaction regime by cosmic radiation (e.g. Seperuelo Duarte et al 2009;Dartois et al 2013Dartois et al , 2015Boduch et al 2015;Mejía et al 2015;Rothard et al 2017, and references therein). Once the efficiencies of these different processes have been quantitatively evaluated in the laboratory for a large number of systems, it is then possible to understand, through modelling, their absolute and relative impact on the chemistry of the interstellar medium.…”

Section: Introductionmentioning

confidence: 99%

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Cosmic ray sputtering yield of interstellar ice mantles

Dartois

Chabot

Barkach

et al. 2021

A&A

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Aims. Cosmic-ray-induced sputtering is one of the important desorption mechanisms at work in astrophysical environments. The chemical evolution observed in high-density regions, from dense clouds to protoplanetary disks, and the release of species condensed on dust grains, is one key parameter to be taken into account in interpretations of both observations and models. Methods. This study is part of an ongoing systematic experimental determination of the parameters to consider in astrophysical cosmic ray sputtering. As was already done for water ice, we investigated the sputtering yield as a function of ice mantle thickness for the two next most abundant species of ice mantles, carbon monoxide and carbon dioxide, which were exposed to several ion beams to explore the dependence with deposited energy. Results. These ice sputtering yields are constant for thick films. It decreases rapidly for thin ice films when reaching the impinging ion sputtering desorption depth. An ice mantle thickness dependence constraint can be implemented in the astrophysical modelling of the sputtering process, in particular close to the onset of ice mantle formation at low visual extinctions.

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Radiolysis and sputtering of carbon dioxide ice induced by swift Ti, Ni, and Xe ions

Cited by 34 publications

References 27 publications

Non-thermal desorption of complex organic molecules

Non-thermal desorption of complex organic molecules

Processing of astrophysical ices by soft X-rays and swift ions

Cosmic ray sputtering yield of interstellar ice mantles

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