Ammonia formation from the reactions of H atoms with N atoms trapped in a solid N2 matrix at 10-30 K

Hiraoka, Kenzo; Yamashita, Akihiro; Yachi, Yoshie; Aruga, Kazuo; Sato, Tetsuya; Muto, Hachizo

doi:10.1086/175531

Cited by 60 publications

(59 citation statements)

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“…Another species that is abundantly formed upon UV-processing, but cannot be detected by means of RAIRS, is N2. Its presence in irradiated ice samples is confirmed by means of TPD; the QMS shows a broad N2 desorption feature that starts at 29 K and peaks around 40 K (Hiraoka et al 1995, see also Fig. 2 for more details on TPD-QMS data).…”

Section: Simultaneous Hydrogenation and Uv-processing Of Pure Nomentioning

confidence: 73%

Simultaneous hydrogenation and UV-photolysis experiments of NO in CO-rich interstellar ice analogues; linking HNCO, OCN⁻, NH₂CHO, and NH₂OH

Fedoseev

Chuang

Dishoeck

et al. 2016

Mon. Not. R. Astron. Soc.

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The laboratory work presented here, simulates the chemistry on icy dust grains as typical for the "CO freeze-out stage" in dark molecular clouds. It differs from previous studies in that solid-state hydrogenation and vacuum UV-photoprocessing are applied simultaneously to co-depositing molecules. In parallel, the reactions at play are described for fully characterized laboratory conditions. The focus is on the formation of molecules containing both carbon and nitrogen atoms, starting with NO in CO-, H2CO-, and CH3OH-rich ices at 13 K. The experiments yield three important conclusions. 1. Without UV-processing hydroxylamine (NH2OH) is formed, as reported previously. 2. With UV-processing (energetic) NH2 is formed through photodissociation of NH2OH. This radical is key in the formation of species with an N-C bond. 3. The formation of three N-C bearing species, HNCO, OCN -and NH2CHO is observed. The experiments put a clear chemical link between these species; OCN -is found to be a direct derivative of HNCO and the latter is shown to have the same precursor as formamide (NH2CHO). Moreover, the addition of VUV competing channels decreases the amount of NO molecules converted into NH2OHby at least one order of magnitude. Consequently, this decrease in NH2OH formation yield directly influences the amount of NO molecules that can be converted into HNCO, OCN -and NH2CHO.

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Section: Simultaneous Hydrogenation and Uv-processing Of Pure Nomentioning

confidence: 73%

Simultaneous hydrogenation and UV-photolysis experiments of NO in CO-rich interstellar ice analogues; linking HNCO, OCN⁻, NH₂CHO, and NH₂OH

Fedoseev

Chuang

Dishoeck

et al. 2016

Mon. Not. R. Astron. Soc.

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“…The sequential hydrogenation of N atoms was first tested at cryogenic temperatures by Hiraoka et al [138] who performed a TPD experiment after the hydrogenation of N atoms trapped in a matrix of solid N 2 . Hidaka et al [139] confirmed the formation of ammonia in a solid N 2 matrix at low temperatures.…”

Section: Surface Chemistry Of Nitrogen Bearing Moleculesmentioning

confidence: 99%

Atom addition reactions in interstellar ice analogues

Linnartz

Ioppolo

Fedoseev

2015

International Reviews in Physical Chemistry

161

142

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It was in 'The Magellanic Cloud' (1955) -a science fiction novel by Stanislaw Lem -that engineers traveling to another star noticed that their spacecraft for unknown reasons overheated. The cause had to be outside the spaceship, but obviously there was only emptiness, at least compared to terrestrial conditions. The space between the stars, the interstellar medium, however, is not completely empty and at the high speed of the spacecraft the cross-section with impacting particles, even from such a dilute environment, was found to be sufficient to cause an overheating. Today, 60 years later, the interstellar medium has been studied in detail by astronomical observations, reproduced in dedicated laboratory experiments and simulated by complex astrochemical models. The space between the stars is, indeed, far from empty; it comprises gas, dust and ice and the molecules detected so far are both small (diatomics) and large (long carbon chains, PAHs and fullerenes), stable and reactive (radicals, ions, and excited molecules) evidencing an exotic and fascinating chemistry, taking place at low densities, low temperatures and experiencing intense radiation fields.Astrochemists explain the observed chemical complexity in space -so far 185 different molecules (not including isotopologues) have been identified -as the cumulative outcome of P a g e | 2 reactions in the gas phase and on icy dust grains. Gas phase models explain the observed abundances of a substantial part of the observed species, but fail to explain the number densities for stable molecules, as simple as water, methanol or acetonitrile -one of the most promising precursor species for the simplest amino acid glycine -as well as larger compounds such as glycolaldehyde, dimethylether and ethylene glycol. Evidence has been found that these and other complex species, including organic ones, form on icy dust grains that act as catalytic sites for molecule formation. It is here where particles 'accrete, meet, and greet' (i.e., freeze out, diffuse and react) upon energetic and non-energetic processing, such as irradiation by vacuum UV light, interaction with impacting particles (atoms, electrons and cosmic rays) or heating.This review paper summarizes the state-of-the-art in laboratory based interstellar ice chemistry. The focus is on atom addition reactions, illustrating how water, carbon dioxide and methanol can form in the solid state at astronomically relevant temperatures, and also the formation of more complex species such as hydroxylamine, an important prebiotic molecule, and glycolaldehyde, the smallest sugar, is discussed. These reactions are particularly relevant during the 'dark' ages of star and planet formation, i.e., when the role of UV light is restricted.A quantitative characterization of such processes is only possible through dedicated laboratory studies, i.e., under full control of a large set of parameters such as temperature, atom-flux, and ice morphology. The resulting numbers, physical and chemical constants, e.g., barrier heights, react...

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“…NH + 4 can only be formed from NH 3 . The presence of solid NH + 4 thus indicates that solid NH 3 was efficiently formed during the ice accretion, presumably by hydrogenation of atomic nitrogen on the grain surface (Hiraoka et al 1995). Whether in dense regions gaseous nitrogen will reside in its molecular or its atomic form depends on the depletion of oxygen, since reactions of atomic nitrogen with OH is an essential step towards N 2 formation (Charnley & Rodgers 2002).…”

Section: Astrophysical Implicationsmentioning

confidence: 99%

Origin of the 6.85 $\mathsf{\mu}$m band near young stellar objects: The ammonium ion (NH_4^+) revisited

Schütte

Khanna

2003

A&A

104

126

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AstrophysicsOrigin of the 6.85 µm band near young stellar objects:The ammonium ion (NH matches two absorption features that are observed towards embedded young stellar objects, i.e., the strong 6.85 µm feature and the 3.26 µm feature. The characteristic redshift with temperature of the interstellar 6.85 µm feature is well reproduced. The abundance of NH + 4 in interstellar ices would be typically 10% relative to H 2 O. The experiments show that the counterions produce little distinct spectral signature but rather a pseudo-continuum if a variety of them is present in a H 2 O dominated environment. The anions could therefore go undetected in IR spectra of interstellar ice. In the ISM, where additional mechanisms such as surface chemistry and additional elements such as sulfur are available many acids and an even wider variety of anions could be produced. These components may be detectable once the ices sublime, e.g., in hot cores.

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Ammonia formation from the reactions of H atoms with N atoms trapped in a solid N2 matrix at 10-30 K

Cited by 60 publications

References 0 publications

Simultaneous hydrogenation and UV-photolysis experiments of NO in CO-rich interstellar ice analogues; linking HNCO, OCN⁻, NH₂CHO, and NH₂OH

Simultaneous hydrogenation and UV-photolysis experiments of NO in CO-rich interstellar ice analogues; linking HNCO, OCN⁻, NH₂CHO, and NH₂OH

Atom addition reactions in interstellar ice analogues

Origin of the 6.85 $\mathsf{\mu}$m band near young stellar objects: The ammonium ion (NH_4^+) revisited

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Ammonia formation from the reactions of H atoms with N atoms trapped in a solid N2 matrix at 10-30 K

Cited by 60 publications

References 0 publications

Simultaneous hydrogenation and UV-photolysis experiments of NO in CO-rich interstellar ice analogues; linking HNCO, OCN−, NH2CHO, and NH2OH

Simultaneous hydrogenation and UV-photolysis experiments of NO in CO-rich interstellar ice analogues; linking HNCO, OCN−, NH2CHO, and NH2OH

Atom addition reactions in interstellar ice analogues

Origin of the 6.85 $\mathsf{\mu}$m band near young stellar objects: The ammonium ion (NH4^+) revisited

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Simultaneous hydrogenation and UV-photolysis experiments of NO in CO-rich interstellar ice analogues; linking HNCO, OCN⁻, NH₂CHO, and NH₂OH

Simultaneous hydrogenation and UV-photolysis experiments of NO in CO-rich interstellar ice analogues; linking HNCO, OCN⁻, NH₂CHO, and NH₂OH

Origin of the 6.85 $\mathsf{\mu}$m band near young stellar objects: The ammonium ion (NH_4^+) revisited