Microwave Spectra of Molecules of Astrophysical Interest: 1. Formaldehyde, Formamide, and Thioformaldehyde

Johnson, Donald R.; Lovas, F. J.; Kirchhoff, William H.

doi:10.1063/1.3253107

Cited by 76 publications

(18 citation statements)

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“…The entries are based on Brünken et al (2003), Müller et al (2000c,b), respectively, with additional measurements in the range of our survey from Cornet & Winnewisser (1980) for all three isotopologues and from Johnson et al (1972) and Dangoisse et al (1978) for the main and 13 C species.…”

Section: Formaldehyde H 2 Comentioning

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

375

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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Section: Formaldehyde H 2 Comentioning

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

375

523

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“…After removing the absorption lines of DMS monomer 16,24 and its isotopologues, Ar-DMS, 25 formaldehyde monomer 19,20 and dimer 21 with isotopologues, and Ar-H 2 CO 22 from the observed spectra, we Table 3. In the case of the D 2 CO-DMS, the observed hyperfine structures were analyzed separately for the ortho and para states of the D 2 CO.…”

Section: B Rotational Spectra Of the H 2 Co-dms And D 2 Co-dms Complmentioning

confidence: 99%

Intermolecular Interaction in the Formaldehyde–Dimethyl Ether and Formaldehyde–Dimethyl Sulfide Complexes Investigated by Fourier Transform Microwave Spectroscopy and ab Initio Calculations

et al. 2015

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The ground-state rotational spectra of the formaldehyde-dimethyl ether: H 2 CO-DME and formaldehyde-dimethyl sulfide: H 2 CO-DMS complexes have been studied by Fourier transform microwave spectroscopy. The a-type and c-type rotational transitions have been assigned for the normal and deutrated formaldehyde containing species of both the complexes. In the case of the H 2 CO-DME, doublets were observed with the splitting of 10~300 kHz, whereas no such splittings were observed for the H 2 CO-DMS, D 2 CO-DME, and D 2 CO-DMS. The observed rotational spectra were found consistent with a structure of C s symmetry with DME or DMS bound to H 2 CO by two types of hydrogen bonds: C-H(DME/DMS)---O(H 2 CO) and O(DME)/S(DMS)---H-C(H 2 CO). TheR cm distances between the centers of mass of the component molecules in the H 2 CO-DME and H 2 CO-DMS complexes were determined to be 3.102 and 3.200 Å, respectively, which are shorter than those in most related complexes. The spectral and NBO analyses showed that the H 2 CO-DMS has stronger charge transfer interaction than the H 2 CO-DME does and that the binding energy of the H 2 CO-DMS is larger than that of the H 2 CO-DME.Keywords: van der Waals complexes, rotational spectra, ortho and para hydrogens, hyperfine structure of the deuterium, weak hydrogen bonding, NBO analysis.

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“…Accurate ground state parameters were found by using 39 (J 6 29, K 6 6) MW transitions [4,17], 97 (J 6 23, K 6 14) submillimeter transitions [18,19], 10,520 (J 6 51, K 6 20) ground state combination differences (GSCD) from the fundamental m 12 band, and 1658 (J 6 51, K 6 19) ground state combination differences from A-type overtone (n 12 = 2 0) transitions. The transitions and combination differences were fitted to the Watson's Hamiltonian [20] (I r representation, A reduction) using a program written by us.…”

Section: High-resolution Analysismentioning

confidence: 99%

Study of vibration–rotation levels in formamide with high resolution FTIR spectroscopy: The ν12, 2ν12, ν11, and ν9 bands

Sztraka

Horneman

2009

Journal of Molecular Spectroscopy

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Microwave Spectra of Molecules of Astrophysical Interest: 1. Formaldehyde, Formamide, and Thioformaldehyde

Cited by 76 publications

References 0 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)

Intermolecular Interaction in the Formaldehyde–Dimethyl Ether and Formaldehyde–Dimethyl Sulfide Complexes Investigated by Fourier Transform Microwave Spectroscopy and ab Initio Calculations

Study of vibration–rotation levels in formamide with high resolution FTIR spectroscopy: The ν12, 2ν12, ν11, and ν9 bands

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