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Articles de revues sur le sujet « Interstellar ices. carbon monoxide »

Auteur : Grafiati
Publié le 21 décembre 2024

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1

Wang, Jia, Andrew M. Turner, Joshua H. Marks, Chaojiang Zhang, N. Fabian Kleimeier, Alexandre Bergantini, Santosh K. Singh, Ryan C. Fortenberry et Ralf I. Kaiser. « Preparation of Acetylenediol (HOCCOH) and Glyoxal (HCOCHO) in Interstellar Analog Ices of Carbon Monoxide and Water ». Astrophysical Journal 967, no 2 (21 mai 2024) : 79. http://dx.doi.org/10.3847/1538-4357/ad3c3e.

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Abstract Enols—tautomers of ketones or aldehydes—are considered key intermediates in the formation of prebiotic sugars and sugar acids. Although laboratory simulation experiments suggest that enols should be ubiquitous in the interstellar medium, the underlying formation mechanisms of enols in interstellar environments are largely elusive. Here, we present the laboratory experiments on the formation of glyoxal (HCOCHO) along with its ynol tautomer acetylenediol (HOCCOH) in interstellar ice analogs composed of carbon monoxide (CO) and water (H2O) upon exposure to energetic electrons as a proxy for secondary electrons generated from Galactic cosmic rays. Utilizing tunable vacuum ultraviolet photoionization reflectron time-of-flight mass spectrometry, glyoxal and acetylenediol were detected in the gas phase during temperature-programmed desorption. Our results reveal the formation pathways of glyoxal via radical–radical recombination of two formyl (HĊO) radicals, and that of acetylenediol via keto-enol-ynol tautomerization. Due to the abundance of carbon monoxide and water in interstellar ices, glyoxal and acetylenediol are suitable candidates for future astronomical searches. Furthermore, the detection of acetylenediol in astrophysically relevant ices advances our understanding for the formation pathways of high-energy tautomers such as enols in deep space.
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Abplanalp, Matthew J., et Ralf I. Kaiser. « On the formation of complex organic molecules in the interstellar medium : untangling the chemical complexity of carbon monoxide–hydrocarbon containing ice analogues exposed to ionizing radiation via a combined infrared and reflectron time-of-flight analysis ». Physical Chemistry Chemical Physics 21, no 31 (2019) : 16949–80. http://dx.doi.org/10.1039/c9cp01793c.

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Schmidt, Fabian, Petra Swiderek, Tarek Scheele et Jan H. Bredehöft. « Mechanisms of methyl formate production during electron-induced processing of methanol–carbon monoxide ices ». Physical Chemistry Chemical Physics 23, no 20 (2021) : 11649–62. http://dx.doi.org/10.1039/d1cp01255j.

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A novel mechanism is proposed for the electron-induced production of methyl formate from CO and CH3OH which is relevant for interstellar ice chemistry. A key-step in this reaction is the formation of an intermediate CH3OCO radical.
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Kuznetsov, O. V., M. M. Evseev, E. A. Batrakova et I. O. Antonov. « Ionization Energy of Reaction Products in an Ethanol–Carbon Monoxide System in Interstellar Ices ». Bulletin of the Lebedev Physics Institute 51, no 3 (mars 2024) : 77–82. http://dx.doi.org/10.3103/s1068335623601826.

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Pilling, Sergio, Eduardo Seperuelo Duarte, Enio F. da Silveira, Emmanuel Balanzat, Hermann Rothard, Alicja Domaracka et Philippe Boduch. « Radiolysis of ammonia-containing ices by heavy cosmic rays inside dense molecular clouds ». Proceedings of the International Astronomical Union 5, S265 (août 2009) : 442–43. http://dx.doi.org/10.1017/s1743921310001237.

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AbstractWe present experimental studies on the interaction of heavy, highly charged and energetic ions (46 MeV 58Ni13+) with interstellar ammonia-containing (H2O:NH3:CO) ice analog in an attempt to simulate the physical chemistry induced by heavy ion cosmic rays inside dense astrophysical environments. The measurements were performed at the heavy ion accelerator GANIL in Caen, France. In-situ analysis have been performed by a Fourier transform infrared spectrometer. The averaged values for the dissociation cross section of water, ammonia and carbon monoxide are determined and the estimated half life for the studied species inside dense molecular clouds is 2-3 × 106 years. The IR spectra of organic residue produced by the radiolysis have revealed, at room temperature, five bands that are tentatively assigned to vibration modes of the zwitterionic glycine (NH3+CH2COO−).
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Bennett, Chris J., Corey S. Jamieson et Ralf I. Kaiser. « AN EXPERIMENTAL INVESTIGATION OF THE DECOMPOSITION OF CARBON MONOXIDE AND FORMATION ROUTES TO CARBON DIOXIDE IN INTERSTELLAR ICES ». Astrophysical Journal Supplement Series 182, no 1 (15 avril 2009) : 1–11. http://dx.doi.org/10.1088/0067-0049/182/1/1.

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Ioppolo, S., B. A. McGuire, M. A. Allodi et G. A. Blake. « THz and mid-IR spectroscopy of interstellar ice analogs : methyl and carboxylic acid groups ». Faraday Discuss. 168 (2014) : 461–84. http://dx.doi.org/10.1039/c3fd00154g.

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A fundamental problem in astrochemistry concerns the synthesis and survival of complex organic molecules (COMs) throughout the process of star and planet formation. While it is generally accepted that most complex molecules and prebiotic species form in the solid phase on icy grain particles, a complete understanding of the formation pathways is still largely lacking. To take full advantage of the enormous number of available THz observations (e.g.,Herschel Space Observatory, SOFIA, and ALMA), laboratory analogs must be studied systematically. Here, we present the THz (0.3–7.5 THz; 10–250 cm−1) and mid–IR (400–4000 cm−1) spectra of astrophysically-relevant species that share the same functional groups, including formic acid (HCOOH) and acetic acid (CH3COOH), and acetaldehyde (CH3CHO) and acetone ((CH3)2CO), compared to more abundant interstellar molecules such as water (H2O), methanol (CH3OH), and carbon monoxide (CO). A suite of pure and mixed binary ices are discussed. The effects on the spectra due to the composition and the structure of the ice at different temperatures are shown. Our results demonstrate that THz spectra are sensitive to reversible and irreversible transformations within the ice caused by thermal processing, suggesting that THz spectra can be used to study the composition, structure, and thermal history of interstellar ices. Moreover, the THz spectrum of an individual species depends on the functional group(s) within that molecule. Thus, future THz studies of different functional groups will help in characterizing the chemistry and physics of the interstellar medium (ISM).
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Collings, M. P., J. W. Dever, M. R. S. McCoustra et H. J. Fraser. « Implications of Ice Morphology for Comet Formation ». Highlights of Astronomy 13 (2005) : 491–94. http://dx.doi.org/10.1017/s1539299600016397.

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AbstractLaboratory surface science under ultra-high vacuum (UHV) conditions allows us to simulate the growth of ices in astrophysical environments. Using the techniques of temperature programmed desorption (TPD), reflection-absorption infrared spectroscopy (RAIRS) and micro-balance methods, we have studied binary ice systems consisting of water (H2O) and variety of other species including carbon monoxide (CO), at astrophysically relevant conditions of temperature and pressure. We present results that demonstrate that the morphology of water ice has an important influence on the behavior of such systems, by allowing processes such as diffusion and trapping that can not be understood through a knowledge of the binding energies of the species alone. Through an understanding of the implications of water ice morphology on the behavior of ice mixtures in the interstellar environment, additional constraints can be placed on the thermodynamic conditions and ice compositions during comet formation.
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Huang, C. H., A. Ciaravella, C. Cecchi-Pestellini, A. Jiménez-Escobar, L. C. Hsiao, C. C. Huang, P. C. Chen, N. E. Sie et Y. J. Chen. « Effects of 150–1000 eV Electron Impacts on Pure Carbon Monoxide Ices Using the Interstellar Energetic-Process System (IEPS) ». Astrophysical Journal 889, no 1 (24 janvier 2020) : 57. http://dx.doi.org/10.3847/1538-4357/ab5dbe.

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Hasegawa, Takeshi, Hiroto Yanagisawa, Takumi Nagasawa, Reo Sato, Naoki Numadate et Tetsuya Hama. « Infrared Band Strengths of Dangling OH Features in Amorphous Water at 20 K ». Astrophysical Journal 969, no 2 (1 juillet 2024) : 134. http://dx.doi.org/10.3847/1538-4357/ad5318.

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Abstract Infrared (IR) spectra of vapor-deposited amorphous water at low temperatures show two weak peaks at around 3720 and 3696 cm−1 assigned to free-OH stretching modes of two- and three-coordinated water molecules (so-called “dangling” OH bonds), respectively, on the ice surface. A recent JWST observation first succeeded in detection of a potential dangling OH feature at 3664 cm−1 for ices in molecular clouds, highlighting the importance of dangling OH bonds in interstellar ice chemistry. A lack of band strengths of these features at low temperatures restricts the quantification of dangling OH bonds from IR spectra, hindering development of a molecular-level understanding of the surface structure and chemistry of ice. Using IR multiple-angle incidence resolution spectrometry, we quantified the band strengths of two- and three-coordinated dangling OH features in amorphous water at 20 K as being 4.6 ± 1.6 × 10−18 and 9.1 ± 1.0 × 10−18 cm molecule−1, respectively. These values are more than an order of magnitude lower than band strengths of bulk-water molecules in ice and liquid water and are similar to those of H2O monomers confined in solid matrices. Adsorption of carbon monoxide with dangling OH bonds results in the appearance of a new broad dangling OH feature at 3680–3620 cm−1, with a band strength of 1.8 ± 0.1 × 10−17 cm molecule−1. The band strengths of dangling OH features determined in this study advance our understanding of the surface structure of interstellar ice analogs and recent IR observations of the JWST.
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Turner, Andrew M., Alexandre Bergantini, Andreas S. Koutsogiannis, N. Fabian Kleimeier, Santosh K. Singh, Cheng Zhu, André K. Eckhardt et Ralf I. Kaiser. « A Photoionization Mass Spectrometry Investigation into Complex Organic Molecules Formed in Interstellar Analog Ices of Carbon Monoxide and Water Exposed to Ionizing Radiation ». Astrophysical Journal 916, no 2 (29 juillet 2021) : 74. http://dx.doi.org/10.3847/1538-4357/ac0537.

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Maity, Surajit, Ralf I. Kaiser et Brant M. Jones. « FORMATION OF KETENE (H2CCO) IN INTERSTELLAR ANALOGOUS METHANE (CH4)-CARBON MONOXIDE (CO) ICES : A COMBINED FTIR AND REFLECTRON TIME-OF-FLIGHT MASS SPECTROSCOPIC STUDY ». Astrophysical Journal 789, no 1 (12 juin 2014) : 36. http://dx.doi.org/10.1088/0004-637x/789/1/36.

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Hudson, R. L., et M. H. Moore. « Laboratory Studies of the Formation of Methanol and Other Organic Molecules by Water+Carbon Monoxide Radiolysis : Relevance to Comets, Icy Satellites, and Interstellar Ices ». Icarus 140, no 2 (août 1999) : 451–61. http://dx.doi.org/10.1006/icar.1999.6144.

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Lambert, David L., Yaron Sheffer, Ronald L. Gilliland et S. R. Federman. « Interstellar carbon monoxide toward zeta Ophiuchi ». Astrophysical Journal 420 (janvier 1994) : 756. http://dx.doi.org/10.1086/173600.

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Crenny, T., et S. R. Federman. « Reanalysis ofCopernicusMeasurements of Interstellar Carbon Monoxide ». Astrophysical Journal 605, no 1 (10 avril 2004) : 278–84. http://dx.doi.org/10.1086/382231.

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M. Wallace, Austin, et Ryan C. Fortenberry. « Computational UV spectra for amorphous solids of small molecules ». Physical Chemistry Chemical Physics 23, no 42 (2021) : 24413–20. http://dx.doi.org/10.1039/d1cp03255k.

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Lamberts, T. « From interstellar carbon monosulfide to methyl mercaptan : paths of least resistance ». Astronomy & ; Astrophysics 615 (juillet 2018) : L2. http://dx.doi.org/10.1051/0004-6361/201832830.

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The 29 reactions linking carbon monosulfide (CS) to methyl mercaptan (CH3SH) via ten intermediate radicals and molecules have been characterized with relevance to surface chemistry in cold interstellar ices. More intermediate species than previously considered are found likely to be present in these ices, such as trans- and cis-HCSH. Both activation and reaction energies have been calculated, along with low-temperature (T > 45 K) rate constants for the radical-neutral reactions. For barrierless radical-radical reactions on the other hand, branching ratios have been determined. The combination of these two sets of information provides, for the first time, quantitative information on the full H + CS reaction network. Early on in this network, that is, early on in the lifetime of an interstellar cloud, HCS is the main radical, while later on this becomes first CH2SH and finally CH3S.
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Collings, M. P., J. W. Dever, H. J. Fraser, M. R. S. McCoustra et D. A. Williams. « Carbon Monoxide Entrapment in Interstellar Ice Analogs ». Astrophysical Journal 583, no 2 (février 2003) : 1058–62. http://dx.doi.org/10.1086/345389.

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Whittet, D. C. B., et W. W. Duley. « Carbon monoxide frosts in the interstellar medium ». Astronomy and Astrophysics Review 2, no 3-4 (1991) : 167–89. http://dx.doi.org/10.1007/bf00872766.

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Marks, Joshua H., Jia Wang, Mikhail M. Evseev, Oleg V. Kuznetsov, Ivan O. Antonov et Ralf I. Kaiser. « Complex Reactive Acids from Methanol and Carbon Dioxide Ice : Glycolic Acid (HOCH2COOH) and Carbonic Acid Monomethyl Ester (CH3OCOOH) ». Astrophysical Journal 942, no 1 (1 janvier 2023) : 43. http://dx.doi.org/10.3847/1538-4357/ac97e3.

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Abstract The formation of complex organic molecules by simulated secondary electrons generated in the track of galactic cosmic rays was investigated in interstellar ice analogs composed of methanol and carbon dioxide. The processed ices were subjected to temperature-programmed desorption to mimic the transition of a cold molecular cloud to a warmer star-forming region. Reaction products were detected as they sublime using photoionization reflectron time-of-flight mass spectrometry. By employing isotopic labeling, tunable photoionization and computed adiabatic ionization energies isomers of C2H4O3 were investigated. Product molecules carbonic acid monomethyl ester (CH3OCOOH) and glycolic acid (HOCH2COOH) were identified. The abundance of the reactants detected in analog interstellar ices and the low irradiation dose necessary to form these products indicates that these molecules are exemplary candidates for interstellar detection. Molecules sharing a tautomeric relationship with glycolic acid, dihydroxyacetaldehyde ((OH)2CCHO), and the enol ethenetriol (HOCHC(OH)2), were not found to form despite ices being subjected to conditions that have successfully produced tautomerization in other ice analog systems.
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Ehrenfreund, Pascale, et Oliver Botta. « From Interstellar Matter To Comets : A Laboratory View ». Highlights of Astronomy 13 (2005) : 488–90. http://dx.doi.org/10.1017/s1539299600016385.

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AbstractComets, formed in the cold outer parts of the solar system, provide a record of pristine material from the parent interstellar cloud. The investigation of outgassing curves from bright comets has provided a relationship to the abundances of interstellar ices and gas phase molecules. However, being porous and stratified in various layers of different densities and temperatures, the out-gassing characteristics of comets can not always be directly reconciled with the interstellar composition. This is due to the structure of the nuclear ice component, which contains different coexisting ice phases, clathrates, and trapped gases. Ices, silicates and carbonaceous compounds – studied through astronomical observations and by laboratory simulations – serve as reference material to obtain information on cometary bulk material. A major fraction of cosmic carbon in the interstellar medium, comets and meteorites seems to be incorporated into complex aromatic networks, which are difficult to observe and to identify spectroscopically. However, recent measurements of the macromolecular structure and soluble organic species in carbonaceous meteorites provide a powerful tool to investigate the link of small bodies in the solar system.
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Arshutkin, L. N. « Study of carbon monoxide formation in interstellar clouds ». Astrophysics 22, no 1 (1985) : 100–107. http://dx.doi.org/10.1007/bf01084466.

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Bodewits, D., J. W. Noonan, P. D. Feldman, M. T. Bannister, D. Farnocchia, W. M. Harris, J. Y. Li, K. E. Mandt, J. Wm Parker et Z. X. Xing. « The carbon monoxide-rich interstellar comet 2I/Borisov ». Nature Astronomy 4, no 9 (20 avril 2020) : 867–71. http://dx.doi.org/10.1038/s41550-020-1095-2.

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Allamandola, Louis J., Max P. Bernstein et Scott A. Sandford. « Photochemical Evolution of Interstellar/Precometary Organic Material ». International Astronomical Union Colloquium 161 (janvier 1997) : 23–47. http://dx.doi.org/10.1017/s0252921100014585.

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AbstractInfrared observations, combined with realistic laboratory simulations, have revolutionized our understanding of interstellar ice and dust, the building blocks of comets. Since comets are thought to be a major source of the volatiles on the primative earth, their organic inventory is of central importance to questions concerning the origin of life. Ices in molecular clouds contain the very simple molecules H2O, CH3OH, CO, CO2, CH4, H2, and probably some NH3and H2CO, as well as more complex species including nitriles, ketones, and esters. The evidence for these, as well as carbonrich materials such as polycyclic aromatic hydrocarbons (PAHs), microdiamonds, and amorphous carbon is briefly reviewed. This is followed by a detailed summary of interstellar/precometary ice photochemical evolution based on laboratory studies of realistic polar ice analogs. Ultraviolet photolysis of these ices produces H2, H2CO, CO2, CO, CH4, HCO, and the moderately complex organic molecules: CH3CH2OH (ethanol), HC(= O)NH2(formamide), CH3C(= O)NH2(acetamide), R-CN (nitriles), and hexamethylenetetramine (HMT, C6H12N4), as well as more complex species including polyoxymethylene and related species (POMs), amides, and ketones. The ready formation of these organic species from simple starting mixtures, the ice chemistry that ensues when these ices are mildly warmed, plus the observation that the more complex refractory photoproducts show lipid-like behavior and readily self organize into droplets upon exposure to liquid water suggest that comets may have played an important role in the origin of life.
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Maity, Surajit, Ralf I. Kaiser et Brant M. Jones. « Formation of complex organic molecules in methanol and methanol–carbon monoxide ices exposed to ionizing radiation – a combined FTIR and reflectron time-of-flight mass spectrometry study ». Physical Chemistry Chemical Physics 17, no 5 (2015) : 3081–114. http://dx.doi.org/10.1039/c4cp04149f.

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The radiation induced chemical processing of methanol and methanol–carbon monoxide ices at 5.5 K exposed to ionizing radiation in the form of energetic electrons and subsequent temperature programmed desorption is reported in this study.
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Mifsud, Duncan V., Péter Herczku, Béla Sulik, Zoltán Juhász, István Vajda, István Rajta, Sergio Ioppolo, Nigel J. Mason, Giovanni Strazzulla et Zuzana Kaňuchová. « Proton and Electron Irradiations of CH4:H2O Mixed Ices ». Atoms 11, no 2 (22 janvier 2023) : 19. http://dx.doi.org/10.3390/atoms11020019.

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The organic chemistry occurring in interstellar environments may lead to the production of complex molecules that are relevant to the emergence of life. Therefore, in order to understand the origins of life itself, it is necessary to probe the chemistry of carbon-bearing molecules under conditions that simulate interstellar space. Several of these regions, such as dense molecular cores, are exposed to ionizing radiation in the form of galactic cosmic rays, which may act as an important driver of molecular destruction and synthesis. In this paper, we report the results of a comparative and systematic study of the irradiation of CH4:H2O ice mixtures by 1 MeV protons and 2 keV electrons at 20 K. We demonstrate that our irradiations result in the formation of a number of new products, including both simple and complex daughter molecules such as C2H6, C3H8, C2H2, CH3OH, CO, CO2, and probably also H2CO. A comparison of the different irradiation regimes has also revealed that proton irradiation resulted in a greater abundance of radiolytic daughter molecules compared to electron irradiation, despite a lower radiation dose having been administered. These results are important in the context of the radiation astrochemistry occurring within the molecular cores of dense interstellar clouds, as well as on outer Solar System objects.
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Maity, Surajit, et Ralf I. Kaiser. « ELECTRON IRRADIATION OF CARBON DISULFIDE-OXYGEN ICES : TOWARD THE FORMATION OF SULFUR-BEARING MOLECULES IN INTERSTELLAR ICES ». Astrophysical Journal 773, no 2 (6 août 2013) : 184. http://dx.doi.org/10.1088/0004-637x/773/2/184.

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Federman, S. R., Jason A. Cardelli, Yaron Sheffer, David L. Lambert et D. C. Morton. « Intersystem transitions of interstellar carbon monoxide toward zeta Ophiuchi ». Astrophysical Journal 432 (septembre 1994) : L139. http://dx.doi.org/10.1086/187531.

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Qasim, D., M. J. A. Witlox, G. Fedoseev, K. J. Chuang, T. Banu, S. A. Krasnokutski, S. Ioppolo, J. Kästner, E. F. van Dishoeck et H. Linnartz. « A cryogenic ice setup to simulate carbon atom reactions in interstellar ices ». Review of Scientific Instruments 91, no 5 (1 mai 2020) : 054501. http://dx.doi.org/10.1063/5.0003692.

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Bergin, Edwin A., Arthur Bosman, Richard Teague, Jenny Calahan, Karen Willacy, L. Ilsedore Cleeves, Kamber Schwarz, Ke Zhang et Simon Bruderer. « The Carbon Isotopic Ratio and Planet Formation ». Astrophysical Journal 965, no 2 (1 avril 2024) : 147. http://dx.doi.org/10.3847/1538-4357/ad3443.

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Abstract We present the first detection of 13CCH in a protoplanetary disk (TW Hya). Using observations of C2H, we measure CCH/13CCH = 65 ± 20 gas with a CO isotopic ratio of 12CO/13CO = 21 ± 5. The TW Hya disk exhibits a gas phase C/O that exceeds unity, and C2H is the tracer of this excess carbon. We confirm that the TW Hya gaseous disk exhibits two separate carbon isotopic reservoirs, as noted previously. We explore two theoretical solutions for the development of this dichotomy. One model represents TW Hya today with a protoplanetary disk exposed to a cosmic-ray ionization rate that is below interstellar as consistent with current estimates. We find that this model does not have sufficient ionization in cold (T < 40 K) layers to activate carbon isotopic fractionation. The second model investigates a younger TW Hya protostellar disk exposed to an interstellar cosmic-ray ionization rate. We find that the younger model has sources of ionization deeper in a colder disk that generates two independent isotopic reservoirs. One reservoir is 12C-enriched carried by methane/hydrocarbon ices, and the other is 13C-enriched carried by gaseous CO. The former potentially provides a source of methane/hydrocarbon ices to power the chemistry that generates the anomalously strong C2H emission in this (and other) disk systems in later stages. The latter provides a source of gaseous 13C-rich material to generate isotopic enrichments in forming giant planets, as recently detected in the super-Jupiter TYC 8998-760-1 b by Zhang et al.
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Israel, F. P., et Th De Graauw. « Carbon Monoxide in the Magellanic Clouds ». Symposium - International Astronomical Union 148 (1991) : 45–49. http://dx.doi.org/10.1017/s007418090019998x.

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Molecular gas is a major constituent of the interstellar medium of all late-type galaxies. Virtually all of it is in the form of cold molecular hydrogen (H2) which today cannot be observed directly. However, the tracer molecule carbon monoxide (CO) (relative abundance 10−5) is easily detected. For the Magellanic Clouds (MCs), CO studies are of specific importance. The Clouds are rich in HI, and if we can establish the presence of significant amounts of H2 as well, this will influence our estimates of the global rate of star formation and its history. Complexes of presently quiescent molecular gas may betray regions primed for star formation, but not yet in action. Detailed studies of the HI, HII and H2 and young star content may provide estimates of star formation efficiences on scales of a kiloparsec.
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Roser, Joe E., Gianfranco Vidali, Giulio Manicò et Valerio Pirronello. « Formation of Carbon Dioxide by Surface Reactions on Ices in the Interstellar Medium ». Astrophysical Journal 555, no 1 (1 juillet 2001) : L61—L64. http://dx.doi.org/10.1086/321732.

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Ahrens, Caitlin, Hypatia Meraviglia et Christopher Bennett. « A Geoscientific Review on CO and CO2 Ices in the Outer Solar System ». Geosciences 12, no 2 (20 janvier 2022) : 51. http://dx.doi.org/10.3390/geosciences12020051.

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Ground-based telescopes and space exploration have provided outstanding observations of the complexity of icy planetary surfaces. This work presents our review of the varying nature of carbon dioxide (CO2) and carbon monoxide (CO) ices from the cold traps on the Moon to Pluto in the Kuiper Belt. This review is organized into five parts. First, we review the mineral physics (e.g., rheology) relevant to these environments. Next, we review the radiation-induced chemical processes and the current interpretation of spectral signatures. The third section discusses the nature and distribution of CO2 in the giant planetary systems of Jupiter and Saturn, which are much better understood than the satellites of Uranus and Neptune, discussed in the subsequent section. The final sections focus on Pluto in comparison to Triton, having mainly CO, and a brief overview of cometary materials. We find that CO2 ices exist on many of these icy bodies by way of magnetospheric influence, while intermixing into solid ices with CH4 (methane) and N2 (nitrogen) out to Triton and Pluto. Such radiative mechanisms or intermixing can provide a wide diversity of icy surfaces, though we conclude where further experimental research of these ices is still needed.
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34

Ferrero, Stefano, Cecilia Ceccarelli, Piero Ugliengo, Mariona Sodupe et Albert Rimola. « Formation of Interstellar Complex Organic Molecules on Water-rich Ices Triggered by Atomic Carbon Freezing ». Astrophysical Journal 960, no 1 (19 décembre 2023) : 22. http://dx.doi.org/10.3847/1538-4357/ad0547.

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Abstract The reactivity of interstellar carbon atoms (C) on water-dominated ices is one of the possible ways to form interstellar complex organic molecules (iCOMs). In this work, we report a quantum chemical study of the coupling reaction of C (3P) with an icy water molecule, alongside possible subsequent reactions with the most abundant closed-shell frozen species (NH3, CO, CO2, and H2), atoms (H, N, and O), and molecular radicals (OH, NH2, and CH3). We found that C reacts spontaneously with the water molecule, resulting in the formation of 3C–OH2, a highly reactive species due to its triplet electronic state. While reactions with the closed-shell species do not show any reactivity, reactions with N and O form CN and CO, respectively, the latter ending up in methanol upon subsequent hydrogenation. The reactions with OH, CH3, and NH2 form methanediol, ethanol, and methanimine, respectively, upon subsequent hydrogenation. We also propose an explanation for methane formation observed in experiments through additions of H to C in the presence of ices. The astrochemical implications of this work are: (i) atomic C on water ice is locked into 3C–OH2, making difficult the reactivity of bare C atoms on icy surfaces, contrary to what is assumed in current astrochemical models; and (ii) the extraordinary reactivity of 3C–OH2 provides new routes toward the formation of iCOMs in a nonenergetic way, in particular ethanol, the mother of other iCOMs once it is in the gas phase.
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35

Zamirri, Lorenzo, Silvia Casassa, Albert Rimola, Mireia Segado-Centellas, Cecilia Ceccarelli et Piero Ugliengo. « IR spectral fingerprint of carbon monoxide in interstellar water–ice models ». Monthly Notices of the Royal Astronomical Society 480, no 2 (19 juillet 2018) : 1427–44. http://dx.doi.org/10.1093/mnras/sty1927.

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36

Ciaravella, A., A. Jiménez-Escobar, G. M. Muñoz Caro, C. Cecchi-Pestellini, R. Candia, S. Giarrusso, M. Barbera et A. Collura. « SOFT X-RAY IRRADIATION OF PURE CARBON MONOXIDE INTERSTELLAR ICE ANALOGUES ». Astrophysical Journal 746, no 1 (18 janvier 2012) : L1. http://dx.doi.org/10.1088/2041-8205/746/1/l1.

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37

Shingledecker, C. N., K. L. K. Lee, J. T. Wandishin, N. Balucani, A. M. Burkhardt, S. B. Charnley, R. Loomis et al. « Detection of interstellar H2CCCHC3N ». Astronomy & ; Astrophysics 652 (août 2021) : L12. http://dx.doi.org/10.1051/0004-6361/202140698.

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Context. The chemical pathways linking the small organic molecules commonly observed in molecular clouds to the large, complex, polycyclic species long suspected of being carriers of the ubiquitous unidentified infrared emission bands remain unclear. Aims. To investigate whether the formation of mono- and polycyclic molecules observed in cold cores could form via the bottom-up reaction of ubiquitous carbon-chain species with, for example, atomic hydrogen, a search is made for possible intermediates in data taken as part of the GOTHAM (GBT Observations of TMC-1: Hunting for Aromatic Molecules) project. Methods. Markov chain Monte Carlo (MCMC) source models were run to obtain column densities and excitation temperatures. Astrochemical models were run to examine possible formation routes, including (a) a novel grain-surface pathway involving the hydrogenation of C6N and HC6N, (b) purely gas-phase reactions between C3N and both propyne (CH3CCH) and allene (CH2CCH2), and (c) via the reaction CN + H2CCCHCCH. Results. We report the first detection of cyanoacetyleneallene (H2CCCHC3N) in space toward the TMC-1 cold cloud using the Robert C. Byrd 100 m Green Bank Telescope. Cyanoacetyleneallene may represent an intermediate between less-saturated carbon chains, such as the cyanopolyynes, that are characteristic of cold cores and the more recently discovered cyclic species, such as cyanocyclopentadiene. Results from our models show that the gas-phase allene-based formation route in particular produces abundances of H2CCCHC3N that match the column density of 2 × 1011 cm−2 obtained from the MCMC source model, and that the grain-surface route yields large abundances on ices that could potentially be important as precursors for cyclic molecules.
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38

Whittet, D. C. B. « Interstellar Dust and the Organic Inventories of Early Solar Systems ». Symposium - International Astronomical Union 213 (2004) : 163–68. http://dx.doi.org/10.1017/s0074180900193192.

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Interstellar dust grains are vectors for cosmic carbon and other biogenic chemical elements. They deliver carbon to protoplanetary disks in various refractory phases (amorphous, graphitic, etc.), and they are coated with icy mantles that contain organic molecules and water. The nature of the organics present in and on the dust appears to be closely related to physical conditions. Complex molecules may be synthesized when simple ices are irradiated. Astronomical observations show that this occurs in the vicinity of certain massive protostars, but it is not known whether our Solar System formed in such a region. Organic matter does not survive cycling though diffuse regions of interstellar space; any organics delivered to the early Earth must have originated in the parent molecular cloud, or in the solar nebula itself. A key question is thus identified: What was the star-formation environment of the Solar System? Possible constraints are briefly discussed.
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39

Sivaraman, Bhalamurugan, Sohan Jheeta, Nigel Mason, Adam Hunniford, Tony Merrigan, Bob McCullough, Daniele Fulvio, Maria Elisabetta Palumbo et Marla Moore. « Electron, proton and ion induced molecular synthesis and VUV spectroscopy of interstellar molecules in the ice phase ». Proceedings of the International Astronomical Union 4, S251 (février 2008) : 451–52. http://dx.doi.org/10.1017/s1743921308022163.

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AbstractPlanets and their moons are constantly subjected to irradiation from both their respective planetary magnetospheres and the solar wind. Energetic particles (electrons, protons and ions) in such radiation may induce complex chemistry within the icy mantles of such bodies, producing many organic compounds. Such processes can be simulated in laboratory experiments. In this report we present recent results from experiments exploring both molecular synthesis and the morphology of such ices.The morphology of any ice may be characterised by IR and Vacuum Ultra-Violet (VUV) spectroscopy. The latter is particularly useful for studying ices in which infrared inactive molecules like oxygen (O2) are common. We have shown that oxygen forms dimers in typical planetary ices and that, in contrast to previous analysis, many of the chemical reactions within the ice involve such dimer (and larger cluster) chemistry. We also present the results of a series of experiments that explore electron, proton and ion irradiation on Solar System relevant ices such as carbon dioxide (CO2) at different temperatures. Infrared spectra recorded before and after irradiation are used to identify and quantify molecules formed in such irradiation, e. g. ozone. These experiments show that the morphology of the ice plays a critical role in the chemistry.
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40

Ferrero, Stefano, Cecilia Ceccarelli, Piero Ugliengo, Mariona Sodupe et Albert Rimola. « Formation of Complex Organic Molecules on Interstellar CO Ices ? Insights from Computational Chemistry Simulations ». Astrophysical Journal 951, no 2 (1 juillet 2023) : 150. http://dx.doi.org/10.3847/1538-4357/acd192.

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Abstract The carbon (3P) atom is a reactive species that, according to laboratory experiments and theoretical calculations, condensates with interstellar ice components. This fact is of uttermost importance for the chemistry in the interstellar medium (ISM) because the condensation reaction is barrierless, and the subsequent species formed are still reactive given their open-shell character. Carbon condensation on CO-rich ices forms the C=C=O (3Σ−) species, which can be easily hydrogenated twice to form ketene (H2CCO). Ketene is very reactive in terrestrial conditions, usually found as an intermediate that is difficult to isolate in chemical synthesis laboratories. These characteristics suggest that ketene can be a good candidate to form interstellar complex organic molecules via a two-step process, i.e., its activation followed by a radical–radical coupling. In this work, reactions between ketene and atomic H and the OH and NH2 radicals on a CO-rich ice model have been explored by means of quantum chemical calculations complemented by kinetic calculations to evaluate if they are favorable in the ISM. Results indicate that the addition of H to ketene (helped by tunneling) to form the acetyl radical (CH3CO) is the most preferred path as the reactions with OH and NH2 possess activation energies (≥9 kJ mol−1) hard to surmount in the ISM conditions unless external processes provide energy to the system. Thus, acetaldehyde (CH3CHO) and, probably, ethanol (CH3CH2OH) formation via further hydrogenations, are the possible unique operating synthetic routes. Moreover, from the computed, relatively large binding energies of OH and NH2 on CO ice, slow diffusion is expected, hampering possible radical–radical couplings with CH3CO. The astrophysical implications of these findings are discussed considering the incoming James Webb Space Telescope observations.
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41

Luna, Ramón, Carlos Millán, Manuel Domingo, Carmina Santonja et Miguel Á. Satorre. « Density and Refractive Index of Carbon Monoxide Ice at Different Temperatures ». Astrophysical Journal 935, no 2 (1 août 2022) : 134. http://dx.doi.org/10.3847/1538-4357/ac8001.

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Abstract This paper is intended to study the density and the refractive index of the solid carbon monoxide in the interval 13–28 K to improve our understanding of the dynamics in the astrophysical environments where they are present. A series of deposition experiments have been performed under high vacuum conditions to study the properties of this ice under astrophysical conditions. Ice density has been experimentally calculated at different deposition temperatures of astrophysical interest, which complement the scarce values present in the literature. The refractive index has also been experimentally determined. The data have been used to obtain an experimental relationship between refractive index and density. Values of density are necessary to interpret observations of astrophysical objects or to design irradiation experiments to understand how irradiation affects ices present in these objects. The experimental relationship found between density and refractive index allows us to estimate density from a known refractive index, even for temperatures not reached using our experimental setup.
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42

Kalvāns, Juris, et Juris Roberts Kalnin. « Temperature Spectra of Interstellar Dust Grains Heated by Cosmic Rays. III. Mixed-composition Grains ». Astrophysical Journal Supplement Series 263, no 1 (21 octobre 2022) : 5. http://dx.doi.org/10.3847/1538-4365/ac92e6.

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Abstract Icy grains in the interstellar medium and star formation regions consist of a variety of materials. Such composite grains interact differently with cosmic-ray (CR) particles compared to simple single-material grains. We aim to calculate the spectra of energies and temperatures of mixed-composition grains undergoing whole-grain heating by CRs. The grains were assumed to consist of a mixture of carbon and olivine, covered by ices consisting of carbon oxides and water. The energy and temperature spectra for grains with radii 0.05, 0.1, and 0.2 μm impacted by CRs were calculated for eight values of column density, relevant to molecular clouds and star-forming cores. The approach takes into account changes in ice thickness and composition with increasing column density. These detailed data for CR interaction with interstellar grains are intended for applications in astrochemical models. The main finding is that a more accurate approach on grain heat capacity and other factors prevent frequent heating of 0.1 μm or larger icy grains to high temperatures.
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43

Neufeld, David A. « COLLISIONAL EXCITATION OF FAR-INFRARED LINE EMISSIONS FROM WARM INTERSTELLAR CARBON MONOXIDE (CO) ». Astrophysical Journal 749, no 2 (30 mars 2012) : 125. http://dx.doi.org/10.1088/0004-637x/749/2/125.

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44

Taj, S., et M. R. S. McCoustra. « Thermal desorption of carbon monoxide from model interstellar ice surfaces : revealing surface heterogeneity ». Monthly Notices of the Royal Astronomical Society 498, no 2 (3 septembre 2020) : 1693–99. http://dx.doi.org/10.1093/mnras/staa2372.

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ABSTRACT Temperature programmed desorption has been used to probe the distribution of binding energies of carbon monoxide (CO) to molecular solid thin films of astrophysical relevance. Measurements are reported for solid water (both compact amorphous solid water and crystalline water), ammonia, and methanol surfaces. Binding energy distributions and optimized pre-exponential factors based on the inversion method are tabulated. These are compared to existing data on these systems and astrophysical conclusions drawn.
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45

Keller, L. P., K. L. Thomas, J. P. Bradley et D. E. Brownlee. « Quantitative analyses of total carbon in interplanetary dust particles ». Proceedings, annual meeting, Electron Microscopy Society of America 50, no 2 (août 1992) : 1724–25. http://dx.doi.org/10.1017/s0424820100133254.

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Interplanetary dust particles (IDPs) collected in the stratosphere are believed to be derived from comets and asteroids. The abundance and chemical state of carbon in IDPs are of particular importance because they provide insight into the processes that have affected carbon from its nucleosynthesis to its incorporation into primitive solar system bodies. Sources of carbon in IDPs may include primary circumstellar condensates (e.g. SiC and graphitic carbons), organic phases derived from the interstellar medium (e.g. polycyclic aromatic hydrocarbons and other residues from radiation-processed ices), biproducts of gas/grain reactions in the solar nebula (e.g. aliphatic hydrocarbons and FeNi carbides), and secondary minerals formed during post-accretional parent body metamorphism (e.g. carbonates). Analysis of carbon in IDPs is complicated by small sample size, loss of volatile components from IDPs during atmospheric entry heating, and terrestrial contamination. The dominant form of carbon observed in IDPs is poorly-crystalline to amorphous material that may be compositionally similar to kerogen.
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46

Andreani, Paola, Lazaros Souvaitzis, Padelis Papadopoulos, Thomas Bisbas, Carlos De Breuck, Bjorn Emonts, Zhi-Yu Zhang, Yusuke Miyamoto et Allison Mann. « The Interstellar and Circumgalactic Media at low and high redshift as traced by Atomic Carbon and Carbon Monoxide ». EPJ Web of Conferences 265 (2022) : 00046. http://dx.doi.org/10.1051/epjconf/202226500046.

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A different chemistry of the interstellar medium (ISM) is expected in the circumgalactic medium (CGM) gas where high-energetic particles (i.e. cosmic rays) seem to be produced in-situ by the hot X-ray gas, as it is observed in the Perseus cluster. This very different astrochemistry, where extreme gas-dust thermal decoupling is expected, and where CO can be destroyed over large massscales, is the subject of the investigation briefly reported here. We introduce an on-going project aiming at studying the properties of the CGM of two clusters at low and high redshift using their molecular gas tracers and thermal emission from dust.
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47

Ferrari, Brian C., Katerina Slavicinska et Christopher J. Bennett. « Role of Suprathermal Chemistry on the Evolution of Carbon Oxides and Organics within Interstellar and Cometary Ices ». Accounts of Chemical Research 54, no 5 (8 février 2021) : 1067–79. http://dx.doi.org/10.1021/acs.accounts.0c00731.

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48

Dartois, E., M. Chabot, T. Id Barkach, H. Rothard, P. Boduch, B. Augé et A. N. Agnihotri. « Cosmic ray sputtering yield of interstellar ice mantles ». Astronomy & ; Astrophysics 647 (mars 2021) : A177. http://dx.doi.org/10.1051/0004-6361/202039535.

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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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Schmidt, Fabian, Petra Swiderek et Jan H. Bredehöft. « Formation of Formic Acid, Formaldehyde, and Carbon Dioxide by Electron-Induced Chemistry in Ices of Water and Carbon Monoxide ». ACS Earth and Space Chemistry 3, no 9 (25 juillet 2019) : 1974–86. http://dx.doi.org/10.1021/acsearthspacechem.9b00168.

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Chaabouni, Henda, Saoud Baouche, Stephan Diana et Marco Minissale. « Reactivity of formic acid (HCOOH) with H atoms on cold surfaces of interstellar interest ». Astronomy & ; Astrophysics 636 (avril 2020) : A4. http://dx.doi.org/10.1051/0004-6361/201936411.

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Context. Formic acid (HCOOH) is the simplest organic carboxylic acid in chemical synthesis and the significant species in interstellar chemistry. HCOOH has been abundantly detected in interstellar ices, dense molecular clouds and star-forming regions. Aims. Laboratory hydrogenation experiments of HCOOH molecules with H atoms were performed with two cryogenic ultra-high vacuum devices on amorphous solid water ices, and highly oriented pyrolytic graphite surfaces. The aim of this work is to study the reactivity of HCOOH molecules with H atoms at low surface temperature 10 K, low surface coverage of one monolayer to three layers, and low H-atom flux of about 3.0 × 1012 molecule cm−2 s−1. Methods. HCOOH and H beams were deposited on cold surfaces held at 10 K, and the condensed films were analyzed by in-situ Reflection Absorption InfraRed Spectroscopy and temperature programmed desorption (TPD) mass spectrometry technique by heating the sample from 10 to 200 K. Results. Using the temperature programmed during exposure desorption technique, we highlight the possible dimerization of HCOOH molecules at low surface temperatures between 10 and 100 K. In our HCOOH+H experiments, we evaluated a consumption of 20–30% of formic acid by comparing the TPD curves at m/z 46 of pure and H-exposed HCOOH ice. Conclusions. The hydrogenation HCOOH+H reaction is efficient at low surface temperatures. The main products identified experimentally are carbon dioxide (CO2) and water (H2O) molecules. CO bearing species CH3OH, and H2CO are also detected mainly on graphite surfaces. A chemical surface reaction route for the HCOOH+H system is proposed to explain the product formation.
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