Wissenschaftliche Biographie

Schütte, Uwe

doi:10.1007/978-3-476-05395-4_1

Cited by 4 publications

(9 citation statements)

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“…Upper limits to the ice column densities of ethanol and acetaldehyde can be given based on the integrated optical depth of their potential features. Schutte et al (1999) give integrated τ values of 2.0±0.3 and 1.6±0.5 cm −1 , respectively. Band strength values of ethanol and acetaldehyde are taken from the literature and used to calculate the column densities of the two features.…”

Section: Com Ice Features In W33amentioning

confidence: 91%

“…In Schutte et al (1999), the acetaldehyde band strength is given as 1.3×10 −17 cm molecule −1 for the CO stretch mode based on data from Wexler (1967). The integrated absorbance ratio of CO stretching / CH 3 s-deforming + CH wagging = 4.32 in pure acetaldehyde at 15 K in laboratory experiments.…”

Section: Com Ice Features In W33amentioning

confidence: 99%

“…In this work we present the infrared spectra of acetaldehyde, ethanol, and dimethyl ether, respectively, CH 3 CHO, CH 3 CH 2 OH, and CH 3 OCH 3 . The choice for these three species, an aldehyde, an alcohol, and an ether, is motivated by previous tentative identifications (Boudin et al 1998;Schutte et al 1999;Öberg et al 2011), their astronomical gas-phase identification and high abundance (e.g. Turner 1991; Gibb et al 2000;Cazaux et al 2003;Bisschop et al 2007b;Taquet et al 2015;Müller et al 2016), and their common formation scheme upon UV irradiation of methanol ice (Öberg et al 2009).…”

Section: Introductionmentioning

confidence: 99%

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Infrared spectra of complex organic molecules in astronomically relevant ice matrices

Scheltinga

Ligterink

Boogert

et al. 2018

A&A

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Context. The number of identified complex organic molecules (COMs) in inter-and circumstellar gas-phase environments is steadily increasing. Recent laboratory studies show that many such species form on icy dust grains. At present only smaller molecular species have been directly identified in space in the solid state. Accurate spectroscopic laboratory data of frozen COMs, embedded in ice matrices containing ingredients related to their formation scheme, are still largely lacking.Aims. This work provides infrared reference spectra of acetaldehyde (CH3CHO), ethanol (CH3CH2OH), and dimethyl ether (CH3OCH3) recorded in a variety of ice environments and for astronomically relevant temperatures, as needed to guide or interpret astronomical observations, specifically for upcoming James Webb Space Telescope observations. Methods. Fourier transform transmission spectroscopy (500-4000 cm −1 / 20-2.5 µm, 1.0 cm −1 resolution) was used to investigate solid acetaldehyde, ethanol and dimethyl ether, pure or mixed with water, CO, methanol, or CO:methanol. These species were deposited on a cryogenically cooled infrared transmissive window at 15 K. A heating ramp was applied, during which IR spectra were recorded until all ice constituents were thermally desorbed. Results. We present a large number of reference spectra that can be compared with astronomical data. Accurate band positions and band widths are provided for the studied ice mixtures and temperatures. Special efforts have been put into those bands of each molecule that are best suited for identification. For acetaldehyde the 7.427 and 5.803 µm bands are recommended, for ethanol the 11.36 and 7.240 µm bands are good candidates, and for dimethyl ether bands at 9.141 and 8.011 µm can be used. All spectra are publicly available in the Leiden Database for Ice.

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Section: Com Ice Features In W33amentioning

confidence: 91%

Section: Com Ice Features In W33amentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Infrared spectra of complex organic molecules in astronomically relevant ice matrices

Scheltinga

Ligterink

Boogert

et al. 2018

A&A

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“…Observations of ices require a background illuminating source for absorption, limiting the number of sight lines that are available for study. Further complications arise when comparing with laboratory spectra, as the peak positions, linewidths, and intensities of molecular ices features are known to be sensitively dependent on temperature, crystal structure of the ice (or lack thereof), and mixing or layering with other species (see, e.g., Ehrenfreund et al 1997, Schutte et al 1999, and Cooke et al 2016. As a result, only a handful of species (H 2 O, CO, CO 2 , CH 4 , CH 3 OH, and NH 3 ) have been definitively detected in interstellar ices.…”

Section: Species Detected In Interstellar Icesmentioning

confidence: 99%

2018 Census of Interstellar, Circumstellar, Extragalactic, Protoplanetary Disk, and Exoplanetary Molecules

McGuire

2018

ApJS

391

290

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To date, 204 individual molecular species, comprised of 16 different elements, have been detected in the interstellar and circumstellar medium by astronomical observations. These molecules range in size from two atoms to seventy, and have been detected across the electromagnetic spectrum from cmwavelengths to the ultraviolet. This census presents a summary of the first detection of each molecular species, including the observational facility, wavelength range, transitions, and enabling laboratory spectroscopic work, as well as listing tentative and disputed detections. Tables of molecules detected in interstellar ices, external galaxies, protoplanetary disks, and exoplanetary atmospheres are provided. A number of visual representations of this aggregate data are presented and briefly discussed in context.

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“…A primary focus in this work is the origin of acetaldehyde in solid state COM chemistry. Acetaldehyde and its fully hydrogen-saturated species, ethanol, have been tentatively identified in interstellar ice mantles through their C-H deformation transitions at ∼7.41 and ∼7.25 µm, respectively (Schutte et al 1999;Öberg et al 2011). Moreover, acetaldehyde is one of the most commonly detected COMs in massive hot cores and giant molecular clouds, such as Orion KL, Sgr B2N, and TMC-1, with a relatively high fractional abundance of χ H 2 ≈10 −10 -10 −9 (Matthews et al 1985;Turner 1991;Ikeda et al 2001;Charnley 2004).…”

Section: Introductionmentioning

confidence: 99%

Formation of complex molecules in translucent clouds: acetaldehyde, vinyl alcohol, ketene, and ethanol via “nonenergetic” processing of C₂H₂ice

Chuang

Fedoseev

Qasim

et al. 2020

A&A

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Context. Complex organic molecules (COMs) have been identified toward high-and low-mass protostars as well as molecular clouds, suggesting that these interstellar species originate from the early stage(s) of starformation. The reaction pathways resulting in COMs described by the formula C 2 H n O, such as acetaldehyde (CH 3 CHO), vinyl alcohol (CH 2 CHOH), ketene (CH 2 CO), and ethanol (CH 3 CH 2 OH), are still under debate. Several of these species have been detected in both translucent and dense clouds, where chemical processes are dominated by (ground-state) atom and radical surface reactions. Therefore, efficient formation pathways are needed to account for their appearance well before the so-called catastrophic CO freeze-out stage starts. Aims. In this work, we investigate the laboratory possible solid-state reactions that involve simple hydrocarbons and OH-radicals along with H 2 O ice under translucent cloud conditions (1≤A V ≤5 and n H ∼10 3 cm −3 ). We focus on the interactions of C 2 H 2 with H-atoms and OH-radicals, which are produced along the H 2 O formation sequence on grain surfaces at 10 K. Methods. Ultra-high vacuum (UHV) experiments were performed to study the surface chemistry observed during C 2 H 2 + O 2 + H codeposition, where O 2 was used for the in-situ generation of OH-radicals. These C 2 H 2 experiments were extended by a set of similar experiments involving acetaldehyde (CH 3 CHO) -an abundant product of C 2 H 2 + O 2 + H codeposition. Reflection absorption infrared spectroscopy (RAIRS) was applied to in situ monitor the initial and newly formed species. After that, a temperature-programmed desorption experiment combined with a Quadrupole mass spectrometer (TPD-QMS) was used as a complementary analytical tool. The IR and QMS spectral assignments were further confirmed in isotope labeling experiments using 18 O 2 . Results. The investigated 10 K surface chemistry of C 2 H 2 with H-atoms and OH-radicals not only results in semi and fully saturated hydrocarbons, such as ethylene (C 2 H 4 ) and ethane (C 2 H 6 ), but it also leads to the formation of COMs, such as vinyl alcohol, acetaldehyde, ketene, ethanol, and possibly acetic acid. It is concluded that OH-radical addition reactions to C 2 H 2 , acting as a molecular backbone, followed by isomerization (i.e., keto-enol tautomerization) via an intermolecular pathway and successive hydrogenation provides a so far experimentally unreported solid-state route for the formation of these species without the need of energetic input. The kinetics of acetaldehyde reacting with impacting H-atoms leading to ketene and ethanol is found to have a preference for the saturated product. The astronomical relevance of the reaction network introduced here is discussed.

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Wissenschaftliche Biographie

Cited by 4 publications

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Infrared spectra of complex organic molecules in astronomically relevant ice matrices

Infrared spectra of complex organic molecules in astronomically relevant ice matrices

2018 Census of Interstellar, Circumstellar, Extragalactic, Protoplanetary Disk, and Exoplanetary Molecules

Formation of complex molecules in translucent clouds: acetaldehyde, vinyl alcohol, ketene, and ethanol via “nonenergetic” processing of C₂H₂ice

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Wissenschaftliche Biographie

Cited by 4 publications

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Infrared spectra of complex organic molecules in astronomically relevant ice matrices

Infrared spectra of complex organic molecules in astronomically relevant ice matrices

2018 Census of Interstellar, Circumstellar, Extragalactic, Protoplanetary Disk, and Exoplanetary Molecules

Formation of complex molecules in translucent clouds: acetaldehyde, vinyl alcohol, ketene, and ethanol via “nonenergetic” processing of C2H2ice

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Formation of complex molecules in translucent clouds: acetaldehyde, vinyl alcohol, ketene, and ethanol via “nonenergetic” processing of C₂H₂ice