Ion irradiation of pure and amorphous CH4 ice relevant for astrophysical environments

2017 ◽  
Vol 19 (20) ◽  
pp. 12845-12856 ◽  
Author(s):  
F. A. Vasconcelos ◽  
S. Pilling ◽  
W. R. M. Rocha ◽  
H. Rothard ◽  
P. Boduch ◽  
...  

We reported results for ion irradiation of CH4 ice with implications for abundance of molecular species in icy objects in the outer Solar System.

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Philippe Boduch ◽  
Enio Frota da Silveira ◽  
Alicja Domaracka ◽  
Oscar Gomis ◽  
Xue Yang Lv ◽  
...  

Our groups in Brazil, France and Italy have been active, among others in the world, in performing experiments on physical-chemical effects induced by fast ions colliding with solids (frozen gases, carbonaceous and organic materials, silicates, etc.) of astrophysical interest. The used ions span a very large range of energies, from a few keV to hundreds MeV. Here we present a summary of the results obtained so far on the formation of oxidants (hydrogen peroxide and ozone) after ion irradiation of frozen water, carbon dioxide and their mixtures. Irradiation of pure water ice produces hydrogen peroxide whatever is the used ion and at different temperatures. Irradiation of carbon dioxide and water frozen mixtures result in the production of molecules among which hydrogen peroxide and ozone. The experimental results are discussed in the light of the relevance they have to support the presence of an energy source for biosphere on Europa and other icy moons in the outer Solar System.


2017 ◽  
Vol 19 (35) ◽  
pp. 24154-24165 ◽  
Author(s):  
F. A. Vasconcelos ◽  
S. Pilling ◽  
W. R. M. Rocha ◽  
H. Rothard ◽  
P. Boduch

We reported results for ion irradiation of N2-rich ices with implications for space weathering of outer solar bodies.


2020 ◽  
Vol 495 (1) ◽  
pp. 40-57
Author(s):  
R C Pereira ◽  
A L F de Barros ◽  
C A P da Costa ◽  
P R B Oliveira ◽  
D Fulvio ◽  
...  

ABSTRACT)3 Acetylene, C2H2, has been observed in the interstellar medium, mostly around young stellar objects, as well as in molecular clouds and cometary comae, representing an important species of astrophysical interest. In this work, we present a laboratory study of the C2H2 radiolysis at 45 K for three different beams and energies: 1.0 MeV H+ and He+, and 1.0 and 1.5 MeV N+ beams. Fourier transform infrared spectroscopy was used for monitoring the molecular changes induced by the ion processing. Two different sample thicknesses were irradiated; for the thicker one, implantation had occurred. Spectra and absorbance evolutions for the thin and thick films are qualitatively different. Four C2H2 bands are observed at 3225, 1954, 1392, and 763 cm−1. The C2H2 compaction and apparent destruction cross-sections are determined. For the case of the H+ beam, the compaction cross-section dominates. Concerning molecular synthesis by irradiation, New product bands were not observed in the thin ice irradiations; for the thicker film ice, the daughter species CH4, C2H4, C3H6, and C4H4 have been identified and their destruction and formation cross-sections determined. The apparent destruction cross-section was found to be a function of the electronic stopping power (Se) as σd ∝ S$_\mathrm{ e}^{3/2}$. The half-life of the C2H2 bombarded by galactic cosmic rays is estimated. The current findings are a contribution to the understanding of how the molecules synthesized upon irradiation of Interstellar and outer Solar system ices participate to the molecular enrichment and to the physicochemical evolution of the Universe.


2021 ◽  
Vol 502 (1) ◽  
pp. 1423-1432
Author(s):  
P R B Oliveira ◽  
R Martinez ◽  
D Fulvio ◽  
E F da Silveira

ABSTRACT Ices are the dominant surface material of many Solar system objects, such as comets and trans-Neptunian objects. They are continuously exposed to ion bombardment by solar wind ions and cosmic rays, which trigger secondary ion emission, contributing to the exosphere formation. Laboratory studies demonstrated the effects of energetic processing of ices at low temperature, showing the production of molecules and free radicals of astrophysical interest. Nitrous oxide (N2O) is one of the molecular species observed in star-forming sites, reason why it may be present in the ices covering some minor bodies in the outer Solar system. In the current work, N2O ice at 10 K was irradiated by energetic (MeV/u) multicharged heavy ions (e.g. 105Rh and 140Ba); the sputtered species were detected and analysed by the TOF-PDMS technique (time-of-flight plasma desorption mass spectrometry). Small positive and negative secondary ions were identified: N+, N2+, NO+, O+, and O−. The bombardment also induces production of ion cluster series: (N2)nR$_{m}^+$, (NO)nR$_{m}^+$, (N2O)nR$_{m}^+$, where R = N+, N2+, NO+, N2O+, Om+ (n up to ∼ 10, m = 1−3). Their yield distributions follow the sum of two decreasing exponentials, one fast -F and another slow -S, suggesting a two-regime formation. Most of the yield distributions have the same pair of exponential decay constants, around kF ∼ 1.4 and kS ∼ 0.15 u−1. Based on this behavior, an emission description for aggregates is proposed, useful to understand the processes by which neutral and ionized molecular species are delivery to the gas phase in space.


1992 ◽  
Vol 56 (1) ◽  
pp. 35-45 ◽  
Author(s):  
G. Strazzulla ◽  
G. Leto ◽  
M. E. Palumbo ◽  
G. A. Baratta

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