Conversion of H<sub>2</sub>CO to CH<sub>3</sub>OH by Reactions of Cold Atomic Hydrogen on Ice Surfaces below 20 K

Hidaka, H.; Watanabe, Naoki; Shiraki, Takahiro; Nagaoka, Akihiro; Kouchi, Akira

doi:10.1086/423889

Cited by 118 publications

(124 citation statements)

References 21 publications

Supporting

Mentioning

109

Contrasting

Unclassified

Order By: Relevance

“…The present paper strongly supports the flux argument given by Hidaka et al (2004). Furthermore, we present a systematic Article published by EDP Sciences study of the physical dependencies involved in the CO-ice hydrogenation to place previous work in a context that allows an extension of solid state astrochemical processes to more complex species.…”

Section: Introductionsupporting

confidence: 87%

“…Hiraoka et al (2002) observed only formaldehyde formation, whereas Watanabe & Kouchi (2002) also found efficient methanol production. In a series of papers, these conflicting results were discussed (Hiraoka et al 2002;Watanabe et al 2003Watanabe et al , 2004 and the prevailing discrepancy between results was proposed to be a consequence of different experimental conditions, most noticeable the adopted H-atom flux (Hidaka et al 2004). Understanding the solid-state formation route to methanol became even more important following an experimental finding that the gas-phase formation route via ionneutral reactions is less efficient than previously estimated and cannot explain the observed interstellar abundances (Geppert et al 2005;Garrod et al 2006).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Hydrogenation reactions in interstellar CO ice analogues

Fuchs¹,

Cuppen²,

Ioppolo³

et al. 2009

A&A

422

517

View full text Add to dashboard Cite

Context. Hydrogenation reactions of CO in inter-and circumstellar ices are regarded as an important starting point in the formation of more complex species. Previous laboratory measurements by two groups of the hydrogenation of CO ices provided controversial results about the formation rate of methanol. Aims. Our aim is to resolve this controversy by an independent investigation of the reaction scheme for a range of H-atom fluxes and different ice temperatures and thicknesses. To fully understand the laboratory data, the results are interpreted theoretically by means of continuous-time, random-walk Monte Carlo simulations. Methods. Reaction rates are determined by using a state-of-the-art ultra high vacuum experimental setup to bombard an interstellar CO ice analog with H atoms at room temperature. The reaction of CO + H into H 2 CO and subsequently CH 3 OH is monitored by a Fourier transform infrared spectrometer in a reflection absorption mode. In addition, after each completed measurement, a temperature programmed desorption experiment is performed to identify the produced species according to their mass spectra and to determine their abundance. Different H-atom fluxes, morphologies, and ice thicknesses are tested. The experimental results are interpreted using Monte Carlo simulations. This technique takes into account the layered structure of CO ice. Results. The formation of both formaldehyde and methanol via CO hydrogenation is confirmed at low temperature (T = 12−20 K). We confirm that the discrepancy between the two Japanese studies is caused mainly by a difference in the applied hydrogen atom flux, as proposed by Hidaka and coworkers. The production rate of formaldehyde is found to decrease and the penetration column to increase with temperature. Temperature-dependent reaction barriers and diffusion rates are inferred using a Monte Carlo physical chemical model. The model is extended to interstellar conditions to compare with observational H 2 CO/CH 3 OH data.

show abstract

Section: Introductionsupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Hydrogenation reactions in interstellar CO ice analogues

Fuchs¹,

Cuppen²,

Ioppolo³

et al. 2009

A&A

422

517

View full text Add to dashboard Cite

show abstract

“…This process has been studied experimentally by Hidaka et al (2004), and was found to be efficient forming methanol at low temperature. Theoretical models show that methanol is abundant in icy grain mantles (CH 3 OH/H 2 O ∼ 0.1) when the atomic hydrogen abundance in the accreting gas is high compared to the CO abundance (Keane & Tielens 2005).…”

Section: Discussionmentioning

confidence: 99%

CH$_\mathsf{3}$OH abundance in low mass protostars

Maret¹,

Ceccarelli²,

Tielens

et al. 2005

A&A

124

151

View full text Add to dashboard Cite

We present observations of methanol lines in a sample of Class 0 low mass protostars. Using a 1-D radiative transfer model, we derive the abundances in the envelopes. In two sources of the sample, the observations can only be reproduced by the model if the methanol abundance is enhanced by about two order of magnitude in the inner hot region of the envelope. Two other sources show similar jumps, although at a lower confidence level. The observations for the other three sources are well reproduced with a constant abundance, but the presence of a jump cannot be ruled out. The observed methanol abundances in the warm gas around low mass protostars are orders of magnitude higher than gas phase chemistry models predict. Hence, in agreement with other evidence, this suggests that the high methanol abundance reflects recent evaporation of ices due to the heating by the newly formed star. The observed abundance ratios of CH 3 OH, H 2 CO and CO are in good agreement with grain surface chemistry models. However, the absolute abundances are more difficult to reproduce and may indicate the presence of multiple ice components in these regions.

show abstract

“…However, the first studies on solid CO hydrogenation by two different groups yielded conflicting results: in one study (Hiraoka et al 2002) only the formation of H 2 CO was reported, whereas in the other study also CH 3 OH was observed (Watanabe and Kouchi 2002). The prevailing discrepancy between these studies was experimentally shown by Fuchs et al (2009) to be a consequence of different experimental conditions, most noticeable the adopted H-atom flux (Hidaka et al 2004). In Fuchs et al (2009), reaction rates have been determined from RAIR data for different ice temperatures and ice thicknesses, as well as H-atom fluxes (see Fig.…”

Section: Surface Formation Of Methanolmentioning

confidence: 98%

Surface formation routes of interstellar molecules: hydrogenation reactions in simple ices

Ioppolo

Cuppen

Linnartz

2011

Rend. Fis. Acc. Lincei

View full text Add to dashboard Cite

It has been a long standing problem in astrochemistry to explain how molecules can form in a highly dilute environment such as the interstellar medium. In recent years it has become clear that not only ion/radical-molecule gas-phase reactions, but also solid state reactions on icy dust grains play an important role in the formation of new species. In order to investigate the underlying processes, laboratory based experiments are needed to simulate surface reactions induced by photon (UV) processing or particle (atom, cosmic ray, electron) bombardment of interstellar ice analogs. Here, the latest research performed on SURFace REaction SImulation DEvice (SURFRESIDE), one of the ultra-high vacuum setups in the Sackler Laboratory for Astrophysics in Leiden is reviewed. The focus is on hydrogenation, i.e., H-atom addition reactions in interstellar ice analogs for astronomically relevant temperatures. We discuss how molecules form when CO and O 2 containing ices are exposed to thermal hydrogen atoms under fully controlled experimental conditions. Surface formation schemes for interstellar relevant species, such as solid methanol, water, and carbon dioxide are investigated and chemical links between molecular species in space are discussed.

show abstract

Conversion of H₂CO to CH₃OH by Reactions of Cold Atomic Hydrogen on Ice Surfaces below 20 K

Cited by 118 publications

References 21 publications

Hydrogenation reactions in interstellar CO ice analogues

Hydrogenation reactions in interstellar CO ice analogues

CH$_\mathsf{3}$OH abundance in low mass protostars

Surface formation routes of interstellar molecules: hydrogenation reactions in simple ices

Contact Info

Product

Resources

About

Conversion of H2CO to CH3OH by Reactions of Cold Atomic Hydrogen on Ice Surfaces below 20 K

Cited by 118 publications

References 21 publications

Hydrogenation reactions in interstellar CO ice analogues

Hydrogenation reactions in interstellar CO ice analogues

CH$_\mathsf{3}$OH abundance in low mass protostars

Surface formation routes of interstellar molecules: hydrogenation reactions in simple ices

Contact Info

Product

Resources

About

Conversion of H₂CO to CH₃OH by Reactions of Cold Atomic Hydrogen on Ice Surfaces below 20 K