High‐Frequency Rotational Spectrum of Thioformaldehyde, H<sub>2</sub>CS, in the Ground Vibrational State

Maeda, Atsuko; Medvedev, Ivan R.; Winnewisser, M.; Lucia, Frank C. De; Herbst, Eric; Müller, H. S. P.; Koerber, Monika; Endres, Christian

doi:10.1086/528684

Cited by 32 publications

(19 citation statements)

References 35 publications

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“…The entry for the main species is based on the extensive account by Maeda et al (2008). A small number of transition frequencies in the 3 mm range were taken from Beers et al (1972).…”

Section: Thioformaldehyde H 2 Csmentioning

confidence: 99%

Complex organic molecules in the interstellar medium: IRAM 30 m line survey of Sagittarius B2(N) and (M)

Беллоче

Müller

Menten

et al. 2013

A&A

385

523

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Context. The discovery of amino acids in meteorites fallen to Earth and the detection of glycine, the simplest of them, in samples returned from a comet to Earth strongly suggest that the chemistry of the interstellar medium is capable of producing such complex organic molecules and that they may be widespread in our Galaxy. Aims. Our goal is to investigate the degree of chemical complexity that can be reached in the interstellar medium, in particular in dense star-forming regions. Methods. We performed an unbiased, spectral line survey toward Sgr B2(N) and (M), two regions where high-mass stars are formed, with the IRAM 30 m telescope in the 3 mm atmospheric transmission window. Partial surveys at 2 and 1.3 mm were performed in parallel. The spectra were analyzed with a simple radiative transfer model that assumes local thermodynamic equilibrium but takes optical depth effects into account. Results. About 3675 and 945 spectral lines with a peak signal-to-noise ratio higher than 4 are detected at 3 mm toward Sgr B2(N) and (M), i.e. about 102 and 26 lines per GHz, respectively. This represents an increase by about a factor of two over previous surveys of Sgr B2. About 70% and 47% of the lines detected toward Sgr B2(N) and (M) are identified and assigned to 56 and 46 distinct molecules as well as to 66 and 54 less abundant isotopologues of these molecules, respectively. In addition, we report the detection of transitions from 59 and 24 catalog entries corresponding to vibrationally or torsionally excited states of some of these molecules, respectively, up to a vibration energy of 1400 cm −1 (2000 K). Excitation temperatures and column densities were derived for each species but should be used with caution. The rotation temperatures of the detected complex molecules typically range from ∼50 to 200 K. Among the detected molecules, aminoacetonitrile, n-propyl cyanide, and ethyl formate were reported for the first time in space based on this survey, as were five rare isotopologues of vinyl cyanide, cyanoacetylene, and hydrogen cyanide. We also report the detection of transitions from within twelve new vibrationally or torsionally excited states of known molecules. Absorption features produced by diffuse clouds along the line of sight are detected in transitions with low rotation quantum numbers of many simple molecules and are modeled with ∼30-40 velocity components with typical linewidths of ∼3-5 km s −1 . Conclusions. Although the large number of unidentified lines may still allow future identification of new molecules, we expect most of these lines to belong to vibrationally or torsionally excited states or to rare isotopologues of known molecules for which spectroscopic predictions are currently missing. Significant progress in extending the inventory of complex organic molecules in Sgr B2(N) and deriving tighter constraints on their location, origin, and abundance is expected in the near future thanks to an ongoing spectral line survey at 3 mm with ALMA in its cycles 0 and 1. The present single-dish surve...

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“…The entry for the main species is based on the extensive account by Maeda et al (2008). A small number of transition frequencies in the 3 mm range were taken from Beers et al (1972).…”

Section: Thioformaldehyde H 2 Csmentioning

confidence: 99%

Complex organic molecules in the interstellar medium: IRAM 30 m line survey of Sagittarius B2(N) and (M)

Беллоче

Müller

Menten

et al. 2013

A&A

385

523

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“…5.3). The rotational constants used to derive the line frequencies were taken from the CDMS Catalog 2 for H 2 CS (Maeda et al 2008) and H 2 13 CS. The H 2 CS dipole moment, μ = 1.6491D, is the one measured by Fabricant et al (1977).…”

Section: H 2 Csmentioning

confidence: 99%

A line confusion limited millimeter survey of Orion KL I. Sulfur carbon chains

Tercero

Cernicharo

Pardo

et al. 2010

A&A

155

250

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We perform a sensitive (line confusion limited), single-side band spectral survey towards Orion KL with the IRAM 30 m telescope, covering the following frequency ranges: 80−115.5 GHz, 130−178 GHz, and 197−281 GHz. We detect more than 14 400 spectral features of which 10 040 have been identified up to date and attributed to 43 different molecules, including 148 isotopologues and lines from vibrationally excited states. In this paper, we focus on the study of OCS, HCS + , H 2 CS, CS, CCS, C 3 S, and their isotopologues. In addition, we map the OCS J = 18−17 line and complete complementary observations of several OCS lines at selected positions around Orion IRc2 (the position selected for the survey). We report the first detection of OCS ν 2 = 1 and ν 3 = 1 vibrationally excited states in space and the first detection of C 3 S in warm clouds. Most of CCS, and almost all C 3 S, line emission arises from the hot core indicating an enhancement of their abundances in warm and dense gas. Column densities and isotopic ratios have been calculated using a large velocity gradient (LVG) excitation and radiative transfer code (for the low density gas components) and a local thermal equilibrium (LTE) code (appropriate for the warm and dense hot core component), which takes into account the different cloud components known to exist towards Orion KL, the extended ridge, compact ridge, plateau, and hot core. The vibrational temperature derived from OCS ν 2 = 1 and ν 3 = 1 levels is 210 K, similar to the gas kinetic temperature in the hot core. These OCS high energy levels are probably pumped by absorption of IR dust photons. We derive an upper limit to the OC 3 S, H 2 CCS, HNCS, HOCS + , and NCS column densities. Finally, we discuss the D/H abundance ratio and infer the following isotopic abundances: 12 C/ 13 C = 45 ± 20, 32 S/ 34 S = 20 ± 6, 32 S/ 33 S = 75 ± 29, and 16 O/ 18 O = 250 ± 135.

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“…6 Laboratory spectroscopic investigations of H 2 CS and its isotopologues have been carried out in the infrared, 7-10 microwave, and millimeter wave ranges. [11][12][13][14][15] Recently, the first high-resolution Fourier transform rovibrational spectrum has been reported 16 for the three lowest vibrational modes, the out-of-plane CH 2 wagging mode ν 4 , the in-plane CH 2 -rocking mode ν 6 , and the CS stretching mode ν 3 . Along with the pure rotational spectrum, these are the only high-resolution spectroscopic data currently available for H 2 CS.…”

Section: Introductionmentioning

confidence: 99%

Theoretical rotation-vibration spectrum of thioformaldehyde

Yachmenev

Polyak

Thiel

2013

The Journal of Chemical Physics

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We present a variational calculation of the first comprehensive T = 300 K rovibrational line list for thioformaldehyde, H2CS. It covers 41,809 rovibrational levels for states up to J(max) = 30 with vibrational band origins up to 5000 cm(-1) and provides the energies and line intensities for 547,926 transitions from the ground vibrational state to these levels. It is based on our previously reported accurate ab initio potential energy surface and a newly calculated ab initio dipole moment surface. Minor empirical adjustments are made to the ab initio equilibrium geometry to reduce systematic errors in the predicted intra-band rotational energy levels. The rovibrational energy levels and transition intensities are computed variationally by using the methods implemented in the computer program TROVE. Transition wavelengths and intensities are found to be in excellent agreement with the available experimental data. The present calculations correctly reproduce the observed resonance effects, such as intensity borrowing, thus reflecting the high accuracy of the underlying ab initio surfaces. We report a detailed analysis of several vibrational bands, especially those complicated by strong Coriolis coupling, to facilitate future laboratory assignments.

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High‐Frequency Rotational Spectrum of Thioformaldehyde, H₂CS, in the Ground Vibrational State

Cited by 32 publications

References 35 publications

Complex organic molecules in the interstellar medium: IRAM 30 m line survey of Sagittarius B2(N) and (M)

Complex organic molecules in the interstellar medium: IRAM 30 m line survey of Sagittarius B2(N) and (M)

A line confusion limited millimeter survey of Orion KL I. Sulfur carbon chains

Theoretical rotation-vibration spectrum of thioformaldehyde

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High‐Frequency Rotational Spectrum of Thioformaldehyde, H2CS, in the Ground Vibrational State

Cited by 32 publications

References 35 publications

Complex organic molecules in the interstellar medium: IRAM 30 m line survey of Sagittarius B2(N) and (M)

Complex organic molecules in the interstellar medium: IRAM 30 m line survey of Sagittarius B2(N) and (M)

A line confusion limited millimeter survey of Orion KL I. Sulfur carbon chains

Theoretical rotation-vibration spectrum of thioformaldehyde

Contact Info

Product

Resources

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High‐Frequency Rotational Spectrum of Thioformaldehyde, H₂CS, in the Ground Vibrational State