The rotational spectrum of acetone: Internal rotation and centrifugal distortion analysis

Vacherand, J. M.; Eijck, B.P. van; Burie, J.; Demaison, J.

doi:10.1016/0022-2852(86)90175-x

Cited by 80 publications

(46 citation statements)

References 17 publications

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“…The synthetic model is consistent with the observations, with one line of 13 We use the JPL entry for the vibrational ground state (tag 58 003 version 3) which is based on Groner et al (2002) with measurements in the range of our survey from Vacherand et al (1986). An entry for the lowest 12 = 1 excited torsional state, based on an analysis presented by Groner et al (2006), was provided by P. Groner.…”

Section: Propyne Ch 3 Cchsupporting

confidence: 55%

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: Propyne Ch 3 Cchsupporting

confidence: 55%

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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“…Notes. Acetone spectroscopic data were taken from the JPL database based on the compilation of several data sets (Groner et al 2002;Oldag & Sutter 1992;Vacherand et al 1986;White 1975;Peter & Dreizler 1965). Upper-state energy E up /k, effective line strength S μ 2 , and spin statistical weight g s are also given.…”

Section: Resultsmentioning

confidence: 99%

Acetone in Orion BN/KL

Peng¹,

Despois²,

Brouillet³

et al. 2013

A&A

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Aims. As one of the prime targets of interstellar chemistry study, Orion BN/KL clearly shows different molecular distributions between large nitrogen-(e.g., C 2 H 5 CN) and oxygen-bearing (e.g., HCOOCH 3 ) molecules. However, acetone (CH 3 ) 2 CO, a special complex O-bearing molecule, has been shown to have a very different distribution from other typical O-bearing molecules in the BN/KL region. Therefore, it is worth investigating acetone in detail at high angular resolutions, which will help us understand the formation of this molecule and its chemical role in the complex BN/KL region. Methods. We searched for acetone within our IRAM Plateau de Bure Interferometer 3 mm and 1.3 mm data sets. Twenty-two acetone lines were searched within these data sets. The angular resolution ranged from 1. 8 × 0. 8 to 6. 0 × 2. 3, and the spectral resolution ranged from 0.4 to 1.9 km s −1 . Results. Nine of the acetone lines appear free of contamination. Three main acetone peaks (Ace-1, 2, and 3) are identified in Orion BN/KL. The new acetone source Ace-3 and the extended emission in the north of the hot core region have been found for the first time. An excitation temperature of about 150 K is determined toward Ace-1 and Ace-2, and the acetone column density is estimated to be 2−4 × 10 16 cm −2 with a relative abundance of 1−6 × 10 −8 toward these two peaks. Acetone is a few times less abundant toward the hot core and Ace-3 compared with Ace-1 and Ace-2. Conclusions. We find that the overall distribution of acetone in BN/KL is similar to that of N-bearing molecules, e.g., NH 3 and C 2 H 5 CN, and very different from those of large O-bearing molecules, e.g., HCOOCH 3 and (CH 3 ) 2 O. Our findings show the acetone distribution is more extended than in previous studies and does not originate only in those areas where both N-bearing and O-bearing species are present. Moreover, because the N-bearing molecules may be associated with shocked gas in Orion BN/KL, this suggests that the formation and/or destruction of acetone may involve ammonia or large N-bearing molecules in a shocked-gas environment.

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“…A third method was introduced by Woods [7,8] and later extended by Vacherand et al [18]. This method is traditionally called IAM, but we will use the notation "CAM" to distinguish it from the coordinate system introduced by Nielsen [9].…”

Section: Numerical Solutionsmentioning

confidence: 99%

“…The energy matrix of the complete Hamiltonian (1) is the sum of matrix elements of the rigid rotor part, of the transformed eigenvalues of each top (15) and of the matrix elements of the two-top operator H l2 as shown in (18).…”

Section: ') (16)mentioning

confidence: 99%

See 1 more Smart Citation

The Microwave Spectrum of trans-2,3-Dimethyloxirane in Torsional Excited States

Hartwig

Dreizler

1996

Zeitschrift Für Naturforschung A

380

331

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The microwave spectrum of trans-2,3-dimethyloxirane (CH 3 CHOCHCH 3 ) in the excited torsional states u 17 = 1 and v i3 -1 has been measured in the range from 8 to 26 GHz and assigned. An analysis of internal rotation splittings of the observed rotational transitions was performed using the internal axis method (or "combined axis method") with a newly developed program accounting for the top-top coupling. The threefold hindering potential V 3 and the direction cosines /. g of the internal rotation axes i with respect to the principal inertia axes g are in a good agreement with the ground state values. Additionally, the sixfold hindering parameter V t was found to be -0.2600(12) kJ/mol. The value of the parameter V[ 2 describing the top-top coupling in the potential function (via V[ 2 sin3r! sin3i 2 ), was determined to -0.4240(6) kJ/mol.

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The rotational spectrum of acetone: Internal rotation and centrifugal distortion analysis

Cited by 80 publications

References 17 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)

Acetone in Orion BN/KL

The Microwave Spectrum of trans-2,3-Dimethyloxirane in Torsional Excited States

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