Deuterated methyl mercaptan (CH<sub>3</sub>SD): Laboratory rotational spectroscopy and search toward IRAS 16293–2422 B

Zakharenko, Olena; Lewen, Frank; Ilyushin, V. V.; Drozdovskaya, M. N.; Jørgensen, J. K.; Schlemmer, Stephan; Müller, H. S. P.

doi:10.1051/0004-6361/201834472

Cited by 9 publications

(14 citation statements)

References 58 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The recent detection of several new sulfur-bearing molecules in the interstellar medium (ISM) (Agundez et al 2018;Cernicharo et al 2018), as well as in comet 67P/Churyumov-Gerasimenko (67P/C-G) by the Rosetta orbiter (Calmonte et al 2016) has, in part, spurred renewed interest in the chemistry of this malodorous element (Hudson & Gerakines 2018;Morgan et al 2018;Dungee et al 2018;Danilovich et al 2018;Drozdovskaya et al 2018;Zakharenko et al 2019;Gorai et al 2017).…”

mentioning

confidence: 99%

Efficient Production of S₈ in Interstellar Ices: The Effects of Cosmic-Ray-driven Radiation Chemistry and Nondiffusive Bulk Reactions

Shingledecker

Lamberts

Laas

et al. 2020

ApJ

View full text Add to dashboard Cite

In this work, we reexamine sulfur chemistry occurring on and in the ice mantles of interstellar dust grains, and report the effects of two new modifications to standard astrochemical models; namely, (a) the incorporation of cosmic ray-driven radiation Corresponding author: Christopher N. Shingledecker cns@mpe.mpg.de Shingledecker et al. et al. (2016). In that work, the authors concluded that this S 2 likely formed in the pre-solar nebula via the radiolysis of species such as H 2 S. In an attempt to improve how astrochemical models treat non-thermal processes, particularly those driven by cosmic rays, we have recently developed methods for including such radiation chemistry in rate-equation-based codes . Our preliminary findings are that the addition of these new mechanisms generally improves the agreement between models and observations (Shingledecker et al. 2018); however, given the novelty of our approach, no modeling studies have yet been done which focus on the effects of cosmic raybombardment on the abundances of sulfur-bearing species in ice mantles. CalmonteAnother major source of uncertainty in current simulations of grain chemistry concerns reactions within the bulk of dust-grain ice mantles. One significant source of uncertainty in such models involves whether or to what degree bulk diffusion is important, and if so, what the underlying mechanism behind this diffusion might be. Commonly, models today typically assume, for example, swapping (Öberg et al. 2009; Fayolle et al. 2011) or diffusion via interstitial sites (Lamberts et al. 2013; Chang & Herbst 2014; Shingledecker et al. 2017), where the energetic barriers to bulk diffusion, E bulk b, are taken to be some fraction of the desorption energy, E D , and are highly uncertain. In Shingledecker et al. (2019a), we attempted to reduce this ambiguity by simulating well-constrained experiments, rather than the ISM. In our preliminary studies reported there, we found that the assumption that radicals within ices react via thermal diffusion leads to generally poor agreement between calculated and empirical results, due to the much slower chemistry in the simulations than what is shown to occur in the lab. Conversely, good agreement with experimental data was achieved by assuming that radicals in the ice react predominantly with their nearest neighbors, i.e. nondiffusively. These results are in qualitative agreement with a recent study by Ghesquière et al. (2018), who concluded that true bulk diffusion does not occur, rather, as temperatures increase, bulk species can be "passively" transported due to structural changes such as pore collapse or crystallization, or can "actively" diffuse along internal surfaces or cracks.This work, therefore, is an attempt to build upon these recent investigations, and to examine what effect (a) cosmic ray-driven radiation chemistry, and (b) the fast, non-diffusive reaction of radicals in

show abstract

mentioning

confidence: 99%

Efficient Production of S₈ in Interstellar Ices: The Effects of Cosmic-Ray-driven Radiation Chemistry and Nondiffusive Bulk Reactions

Shingledecker

Lamberts

Laas

et al. 2020

ApJ

View full text Add to dashboard Cite

show abstract

“…2019, Zakharenko et al performed a laboratory study on the deuterated CH 3 SD species recording in the 150−510 GHz frequency range using the Cologne millimeter wave spectrometer212 . More than 4000 transitions up to v t = 2 were analyzed and fitted using the RAM36 program.…”

mentioning

confidence: 99%

“…More than 4000 transitions up to v t = 2 were analyzed and fitted using the RAM36 program. Using these spectroscopic data, the search for CH 3 SD in data from the ALMA, Protostellar Interferometric Line Survey (PILS) of the protostar IRAS 16293−2422, was performed212 .While methyl mercaptan has not been observed to date on any of the other Solar System planets, it could be used as a biomaker for detecting evidence of Martian life213 .Acetone (CH 3 COCH 3 ) is a two-top internal rotor molecule, which was first reported to be in the ISM by Combes et al26 in Sgr B2. The column density was estimated to be 5 x 10 13 cm -2 , corresponding to a fractional abundance with respect to H 2 of 5 x 10 -11 .…”

mentioning

confidence: 99%

Spectroscopy of Interstellar Internal Rotors: An Important Tool for Investigating Interstellar Chemistry

Kleiner

2019

ACS Earth Space Chem.

View full text Add to dashboard Cite

This paper is a review of molecules with internal rotors detected or tentatively detected with upper limits in the interstellar medium. Internal rotor molecules containing one or two methyl groups are present at each of the different phases leading to stellar and planetary formation, from the molecular clouds to the star and its planets. They are also found in comets and asteroids. They represent a ubiquitous hydrogen-rich substituent in many complex organic molecules. This paper shows how high resolution spectra (mainly in the microwave, millimeter and sub-millimeter wave range) are analyzed in the laboratory and what theoretical methods can be used to properly reproduce the spectra. We also present a range of examples of important methyl rotors studied and how they can be used as tools to study the chemistry of interstellar medium.

show abstract

“…The 12 C/ 13 C and 32 S/ 34 S substitutions affect mainly B and C among the rotational constants, whereas H/D substitution significantly affects also the A rotational constant and Dab (the change in sign of Dab was discussed in detail in ref. [45]). Thus it is not surprising that the DK parameter of CH3SD is the most deviating among thequartic centrifugal distortion parameters, which in general agree rather well especially for the main, 13 C and 34 S isotopologues.…”

Section: Assignments and Fittingmentioning

confidence: 99%

“…Later millimetre-wave studies [42,43] as well as a work by some of the current authors covering sections of the 1.1−1.8 THz region [44] were carried out to provide accurate transition frequencies for radio-astronomical observations. More recently, we performed new measurements on CH3SD [45] in the 150−510 GHz region to facilitate astronomical searches for this methyl mercaptan isotopic species. In addition, we recorded new spectra of CH3SH covering 49−510 GHz to reach higher J and K rotational quantum numbers for astronomical observations [46], and also to analyse the intricate perturbations between higher torsional states and lower-lying small amplitude vibrations that manifest themselves already in lower torsional states, especially vt = 2, via torsional interactions.…”

Section: Introductionmentioning

confidence: 99%

Rotational spectrum of isotopic methyl mercaptan, ¹³CH₃SH, in the laboratory and towards Sagittarius B2(N2)

et al. 2020

Self Cite

View full text Add to dashboard Cite

Methyl mercaptan (CH3SH) is a known interstellar molecule with abundances high enough that the detection of some of its minor isotopologues is promising. The present study aims to provide accurate spectroscopic parameters for the 13 CH3SH isotopologue to facilitate its identification in the interstellar medium at millimetre and submillimetre wavelengths. Through careful analysis of recent CH3SH spectra from 49−510 GHz and 1.1−1.5 THz recorded at natural isotopic composition, extensive assignments were possible not only for the ground torsional state of 13 CH3SH, but also in the first and second excited states. The torsionrotation spectrum displays complex structure due to the large-amplitude internal rotation of the 13 CH3 group, similar to the main and other minor isotopic species of methyl mercaptan. The assigned transition frequencies have been fitted to within experimental error with a 52parameter model employing the RAM36 programme. With predictions based on this fit, 13 CH3SH was searched for in spectra from the Atacama Large Millimetre/submillimetre Array (ALMA) towards the Galactic centre source Sgr B2(N2). Several transitions were expected to be observable, but all of them turned out to be severely blendedwith emission from other species, which prevents us from identifying 13 CH3SH in this source.

show abstract

Deuterated methyl mercaptan (CH₃SD): Laboratory rotational spectroscopy and search toward IRAS 16293–2422 B

Cited by 9 publications

References 58 publications

Efficient Production of S₈ in Interstellar Ices: The Effects of Cosmic-Ray-driven Radiation Chemistry and Nondiffusive Bulk Reactions

Efficient Production of S₈ in Interstellar Ices: The Effects of Cosmic-Ray-driven Radiation Chemistry and Nondiffusive Bulk Reactions

Spectroscopy of Interstellar Internal Rotors: An Important Tool for Investigating Interstellar Chemistry

Rotational spectrum of isotopic methyl mercaptan, ¹³CH₃SH, in the laboratory and towards Sagittarius B2(N2)

Contact Info

Product

Resources

About

Deuterated methyl mercaptan (CH3SD): Laboratory rotational spectroscopy and search toward IRAS 16293–2422 B

Cited by 9 publications

References 58 publications

Efficient Production of S8 in Interstellar Ices: The Effects of Cosmic-Ray-driven Radiation Chemistry and Nondiffusive Bulk Reactions

Efficient Production of S8 in Interstellar Ices: The Effects of Cosmic-Ray-driven Radiation Chemistry and Nondiffusive Bulk Reactions

Spectroscopy of Interstellar Internal Rotors: An Important Tool for Investigating Interstellar Chemistry

Rotational spectrum of isotopic methyl mercaptan, 13CH3SH, in the laboratory and towards Sagittarius B2(N2)

Contact Info

Product

Resources

About

Deuterated methyl mercaptan (CH₃SD): Laboratory rotational spectroscopy and search toward IRAS 16293–2422 B

Efficient Production of S₈ in Interstellar Ices: The Effects of Cosmic-Ray-driven Radiation Chemistry and Nondiffusive Bulk Reactions

Efficient Production of S₈ in Interstellar Ices: The Effects of Cosmic-Ray-driven Radiation Chemistry and Nondiffusive Bulk Reactions

Rotational spectrum of isotopic methyl mercaptan, ¹³CH₃SH, in the laboratory and towards Sagittarius B2(N2)