Reaction kinetics and isotope effect of water formation by the surface reaction of solid H<sub>2</sub>O<sub>2</sub>with H atoms at low temperatures

Oba, Yasuhiro; Osaka, Kazuya; Watanabe, Naoki; Chigai, Takeshi; Kouchi, Akira

doi:10.1039/c3fd00112a

Cited by 33 publications

(44 citation statements)

References 62 publications

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“…In a co-deposition experiment, ice molecules and atoms or radicals are deposited simultaneously and depending on the applied ratio this allows each deposited species to be available for the reaction. The latter is generally closer to the processes taking place in space (although not exclusively) and as previously mentioned often allows to monitor both intermediate and final products of the reactions [093,102,128,130].…”

Section: P a G E | 18mentioning

confidence: 99%

“…Over the last 15 years, particularly five specific surface reaction schemes have been studied in much detail: i) the formation of hydrogen peroxide and water upon hydrogenation (deuteration) of oxygen-containing ice, i.e., O+H, O 2 +H and O 3 +H [85][86][87][88][89][90][91][92][93][94][95][96][97][98][99][100][101][102]; ii) the formation of formaldehyde and methanol upon sequential hydrogenation of CO ice [025,[103][104][105][106][107][108][109][110][111][112][113][114]; iii) the formation of carbon dioxide, P a g e | 16…”

Section: State-of-the-artmentioning

confidence: 99%

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Atom addition reactions in interstellar ice analogues

Linnartz

Ioppolo

Fedoseev

2015

International Reviews in Physical Chemistry

163

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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Section: P a G E | 18mentioning

confidence: 99%

Section: State-of-the-artmentioning

confidence: 99%

Atom addition reactions in interstellar ice analogues

Linnartz

Ioppolo

Fedoseev

2015

International Reviews in Physical Chemistry

163

142

View full text Add to dashboard Cite

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Section: Scenariomentioning

confidence: 99%

“…These pathways include reactions with activation energy barriers, and thus proceed through quantum tunneling (Oba et al 2012(Oba et al , 2014. The barrier-mediated reactions favor hydrogenation over deuteration, because deuterium is twice heavier than hydrogen (Oba et al 2014). In addition, once water is formed, it does not efficiently react with atomic deuterium to be deuterated at low temperatures, unlike formaldehyde and methanol (Nagaoka et al 2005).…”

Section: Scenariomentioning

confidence: 99%

Reconstructing the history of water ice formation from HDO/H₂O and D₂O/HDO ratios in protostellar cores

Furuya

Dishoeck

Aikawa

2016

A&A

137

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Recent interferometer observations have found that the D 2 O/HDO abundance ratio is higher than that of HDO/H 2 O by about one order of magnitude in the vicinity of low-mass protostar NGC 1333-IRAS 2A, where water ice has sublimated. Previous laboratory and theoretical studies show that the D 2 O/HDO ice ratio should be lower than the HDO/H 2 O ice ratio, if HDO and D 2 O ices are formed simultaneously with H 2 O ice. In this work, we propose that the observed feature, D 2 O/HDO > HDO/H 2 O, is a natural consequence of chemical evolution in the early cold stages of low-mass star formation as follows: 1) majority of oxygen is locked up in water ice and other molecules in molecular clouds, where water deuteration is not efficient; and 2) water ice formation continues with much reduced efficiency in cold prestellar/protostellar cores, where deuteration processes are highly enhanced as a result of the drop of the ortho-para ratio of H 2 , the weaker UV radiation field, etc. Using a simple analytical model and gas-ice astrochemical simulations, which traces the evolution from the formation of molecular clouds to protostellar cores, we show that the proposed scenario can quantitatively explain the observed HDO/H 2 O and D 2 O/HDO ratios. We also find that the majority of HDO and D 2 O ices are likely formed in cold prestellar/protostellar cores rather than in molecular clouds, where the majority of H 2 O ice is formed. This work demonstrates the power of the combination of the HDO/H 2 O and D 2 O/HDO ratios as a tool to reveal the past history of water ice formation in the early cold stages of star formation, and when the enrichment of deuterium in the bulk of water occurred. Further observations are needed to explore if the relation, D 2 O/HDO > HDO/H 2 O, is common in low-mass protostellar sources.

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“…7 Water is the most abundant species in interstellar ices and its Markus Meuwly (University of Basel) introduced the final paper of the morning session which provided a complementary theoretical discussion concerning the diffusion of oxygen atoms during water formation in amorphous interstellar ices. 8 Their work supports the experimental results of Congiu and co-authors on the diffusion of O atoms at low temperatures.…”

mentioning

confidence: 99%

Highlights from Faraday Discussion 168: Astrochemistry of Dust, Ice and Gas, Leiden, The Netherlands, April 2014

2014

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Reaction kinetics and isotope effect of water formation by the surface reaction of solid H₂O₂with H atoms at low temperatures

Cited by 33 publications

References 62 publications

Atom addition reactions in interstellar ice analogues

Atom addition reactions in interstellar ice analogues

Reconstructing the history of water ice formation from HDO/H₂O and D₂O/HDO ratios in protostellar cores

Highlights from Faraday Discussion 168: Astrochemistry of Dust, Ice and Gas, Leiden, The Netherlands, April 2014

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Reaction kinetics and isotope effect of water formation by the surface reaction of solid H2O2with H atoms at low temperatures

Cited by 33 publications

References 62 publications

Atom addition reactions in interstellar ice analogues

Atom addition reactions in interstellar ice analogues

Reconstructing the history of water ice formation from HDO/H2O and D2O/HDO ratios in protostellar cores

Highlights from Faraday Discussion 168: Astrochemistry of Dust, Ice and Gas, Leiden, The Netherlands, April 2014

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Reaction kinetics and isotope effect of water formation by the surface reaction of solid H₂O₂with H atoms at low temperatures

Reconstructing the history of water ice formation from HDO/H₂O and D₂O/HDO ratios in protostellar cores