Detection of Interstellar Thioformaldehyde

Sinclair, MW; Fourikis, N.; Ribes, J. C.; Robinson, B. J.; Brown, R. G.; Godfrey, P. D.

doi:10.1071/ph730085

Cited by 104 publications

(41 citation statements)

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“…1,2 Few lines of H 2 CS have also been identified in the Orion KL nebula [3][4][5] and in the atmosphere of the comet Hale-Bopp. 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.…”

Section: Introductionmentioning

confidence: 96%

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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Section: Introductionmentioning

confidence: 96%

Theoretical rotation-vibration spectrum of thioformaldehyde

Yachmenev

Polyak

Thiel

2013

The Journal of Chemical Physics

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“…The four molecules in this paper (CH 2 CHCN, CH 2 CN, CH 3 CCH, and H 2 CS) were identified in space for the first time towards Sagittarius B2 (Gardner & Winnewisser 1975;Irvine et al 1988;Snyder & Buhl 1973;Sinclair et al 1973) by Article published by EDP Sciences observation of rotational transitions. The microwave spectrum of all these species has been extensively studied in the laboratory so that their spectroscopic properties are accurately known; see a compilation in the JPL and Cologne databases for molecular spectroscopy (Pickett et al 1998;Müller et al 2005).…”

Section: Spectroscopy and Observationsmentioning

confidence: 99%

Detection of circumstellar CH₂CHCN, CH₂CN, CH₃CCH, and H₂CS

Agúndez

Fonfría

Cernicharo

et al. 2008

A&A

132

135

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Aims. We report on the detection of vinyl cyanide (CH 2 CHCN), cyanomethyl radical (CH 2 CN), methylacetylene (CH 3 CCH), and thioformaldehyde (H 2 CS) in the C-rich star IRC +10216. These species, which are all known to exist in dark clouds, were detected for the first time in the circumstellar envelope around an AGB star. Methods. The four molecules were detected through pure rotational transitions in the course of a λ 3 mm line survey carried out with the IRAM 30-m telescope. The molecular column densities were derived by constructing rotational temperature diagrams. A detailed chemical model of the circumstellar envelope is used to analyze the formation of these molecular species. Results. We have found column densities in the range 5 × 10 12 −2 × 10 13 cm −2 , which translates to fractional abundances relative to H 2 of several 10 −9 . The chemical model is reasonably successful in explaining the derived abundances through gas phase synthesis in the cold outer envelope. We also find that some of these molecules, CH 2 CHCN and CH 2 CN, are most probably excited through infrared pumping to excited vibrational states. Conclusions. The detection of these species stresses the similarity between the molecular content of cold dark clouds and C-rich circumstellar envelopes. However, some differences in the chemistry are indicated by partially saturated carbon chains being present in IRC +10216 at a lower level than those that are highly unsaturated, while in TMC-1 both types of species have comparable abundances.

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“…Thioformaldehyde is also found toward the Galactic center, in well-known hot cores such as the Compact Ridge in Orion KL, and in outflows such as those of the Cepheus A star-forming region, where it is a tracer of high-velocity gas (Codella et al 2005) and is either desorbing from grains or rapidly forming in the gas-phase after mantle evaporation. Although an interstellar search for thioformaldehyde was carried out ( Evans et al 1970) soon after the first microwave laboratory study (Johnson & Powell 1970), the first interstellar detection was reported a few years later (Sinclair et al 1973). Meanwhile, the extension of the known rotational spectrum to higher microwave and millimeter-wave frequencies (Johnson et al 1971;Beers et al 1972) allowed predictions of a large number of unmeasured lines to be made available for interstellar identification of thioformaldehyde .…”

Section: à9mentioning

confidence: 99%

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

Maeda

Medvedev

Winnewisser

et al. 2008

ASTROPHYS J SUPPL S

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Pure rotational transitions have been measured for the normal isotopologue of thioformaldehyde, H 12 2 C 32 S, in the ground vibrational state in the 110-370 GHz, 570-670 GHz, and 850-930 GHz frequency ranges. A global data set has been constructed consisting of prior microwave and millimeter-wave transitions, the submillimeter-wave and terahertz (THz) transitions reported here, and far-infrared data and ground state combination differences. The 783 different transition frequencies in the data set were fit to Watson's S-reduced Hamiltonian with 20 parameters, resulting in a dimensionless weighted root-mean-square deviation of 0.78. New frequency predictions have been made for astronomical observations based on the molecular parameters obtained in the present study.

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Detection of Interstellar Thioformaldehyde

Cited by 104 publications

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Theoretical rotation-vibration spectrum of thioformaldehyde

Theoretical rotation-vibration spectrum of thioformaldehyde

Detection of circumstellar CH₂CHCN, CH₂CN, CH₃CCH, and H₂CS

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

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Detection of Interstellar Thioformaldehyde

Cited by 104 publications

References 0 publications

Theoretical rotation-vibration spectrum of thioformaldehyde

Theoretical rotation-vibration spectrum of thioformaldehyde

Detection of circumstellar CH2CHCN, CH2CN, CH3CCH, and H2CS

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

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Detection of circumstellar CH₂CHCN, CH₂CN, CH₃CCH, and H₂CS

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