Rotational Spectra of Selected Isotopic Species of Vinyl Cyanide: Molecular Structure and Quadrupole Hyperfine Structure

Colmont, J.-M.; Wlodarczak, G.; Priem, D.; Müller, H. S. P.; Tien, E.H.; Richards, Richard J.; Gerry, Michael C. L.

doi:10.1006/jmsp.1996.7174

Cited by 38 publications

(45 citation statements)

References 9 publications

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“…This work includes in particular laboratory data from Gerry & Winnewisser (1973), Baskakov (1996), and Cazzoli & Kisiel (1988) providing rest frequencies for the main isotopic species in the range of our line survey. In the case of the 13 C isotopologues, Colmont et al (1997) cover additional frequency ranges similar to the ones of our survey.…”

Section: Vinyl Cyanide C 2 H 3 Cnsupporting

confidence: 69%

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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Section: Vinyl Cyanide C 2 H 3 Cnsupporting

confidence: 69%

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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“…The transitions were easily found because of the extensive data set from previous laboratory studies [8][9][10][11][12][13][14]. The maximum J and K a values were 80 and 30, respectively.…”

Section: Observed Laboratory Spectra and Analysismentioning

confidence: 99%

Rotational spectroscopy of isotopic vinyl cyanide, H2CCHCN, in the laboratory and in space

Müller

Беллоче

Menten

et al. 2008

Journal of Molecular Spectroscopy

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a b s t r a c tThe rotational spectra of singly substituted 13 C and 15 N isotopic species of vinyl cyanide have been studied in natural abundances between 64 and 351 GHz. In combination with previous results, greatly improved spectroscopic parameters have been obtained which in turn helped to identify transitions of the 13 C species for the first time in space through a molecular line survey of the extremely line-rich interstellar source Sagittarius B2(N) in the 3 mm region with some additional observations at 2 mm. The 13 C species are detected in two compact ($2.3 00 ), hot (170 K) cores with a column density of $3:8 Â 10 16 and 1:1 Â 10 16 cm À2 , respectively. In the main source, the so-called ''Large Molecule Heimat", we derive an abundance of 2:9 Â 10 À9 for each 13 C species relative to H 2 . An isotopic ratio 12 C/ 13 C of 21 has been measured. Based on a comparison to the column densities measured for the 13 C species of ethyl cyanide also detected in this survey, it is suggested that the two hot cores of Sgr B2(N) are in different evolutionary stages. Supplementary laboratory data for the main isotopic species recorded between 92 and 342 GHz permitted an improvement of its spectroscopic parameters as well.

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“…1) were used. These entries are based on laboratory work by Gerry & Winnewisser (1973), Baskakov et al (1996), and Cazzoli & Kisiel (1988) for the main isotopic species and Colmont et al (1997) for the 13 C isotopologues. For CH 2 CHCN, most lines were optically thick and were not modeled, as previously discussed.…”

Section: Two Distinct Lines Of H Cs 2 13mentioning

confidence: 99%

The ¹²C/¹³C Ratio in Sgr B2(N): Constraints for Galactic Chemical Evolution and Isotopic Chemistry

Halfen

Woolf

Ziurys

2017

ApJ

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A study has been conducted of 12 C/ 13 C ratios in five complex molecules in the Galactic center. H 2 CS, CH 3 CCH, NH 2 CHO, CH 2 CHCN, and CH 3 CH 2 CN and their 13 C-substituted species have been observed in numerous transitions at 1, 2, and 3 mm, acquired in a spectral-line survey of Sgr B2(N), conducted with the telescopes of the Arizona Radio Observatory (ARO). Between 22 and 54 individual, unblended lines for the 12 C species and 2-54 for 13 C-substituted analogs were modeled in a global radiative transfer analysis. All five molecules were found to consistently exhibit two velocity components near V LSR ∼ 64 and 73 km s −1 , with column densities ranging from N tot ∼ 3 × 10 14 −4 × 10 17 cm −2 and ∼2 × 10 13 −1 × 10 17 cm −2 for the 12 C and 13 C species, respectively. Based on 14 different isotopic combinations, ratios were obtained in the range 12 C/ 13 C = 15±5 to 33±13, with an average value of 24±7, based on comparison of column densities. These measurements better anchor the 12 C/ 13 C ratio at the Galactic center, and suggest a slightly revised isotope gradient of 12 C/ 13 C = 5.21(0.52) D GC + 22.6(3.3). As indicated by the column densities, no preferential 13 C enrichment was found on the differing carbon sites of CH 3 CCH, CH 2 CHCN, and CH 3 CH 2 CN. Because of the elevated temperatures in Sgr B2(N), 13 C isotopic substitution is effectively "scrambled," diminishing chemical fractionation effects. The resulting ratios thus reflect stellar nucleosynthesis and Galactic chemical evolution, as is likely the case for most warm clouds.

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Rotational Spectra of Selected Isotopic Species of Vinyl Cyanide: Molecular Structure and Quadrupole Hyperfine Structure

Cited by 38 publications

References 9 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)

Rotational spectroscopy of isotopic vinyl cyanide, H2CCHCN, in the laboratory and in space

The ¹²C/¹³C Ratio in Sgr B2(N): Constraints for Galactic Chemical Evolution and Isotopic Chemistry

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Rotational Spectra of Selected Isotopic Species of Vinyl Cyanide: Molecular Structure and Quadrupole Hyperfine Structure

Cited by 38 publications

References 9 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)

Rotational spectroscopy of isotopic vinyl cyanide, H2CCHCN, in the laboratory and in space

The 12C/13C Ratio in Sgr B2(N): Constraints for Galactic Chemical Evolution and Isotopic Chemistry

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The ¹²C/¹³C Ratio in Sgr B2(N): Constraints for Galactic Chemical Evolution and Isotopic Chemistry