The laboratory millimeter- and submillimeter-wave spectrum of CH3OD

Anderson, Todd; Crownover, Richard L.; Herbst, Eric; Lucia, Frank C. De

doi:10.1086/191269

Cited by 46 publications

(23 citation statements)

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“…a The 1σ uncertainties (in parentheses) were estimated on the basis of signal to noise, line profile shape, and degree of blending with background lines. b Calculated from the spectroscopic constants in Table 3. laboratory measurements show that he was observing instead cyanic acid: First, the astronomical frequency at 83900 MHz is in excellent agreement with that of HOCN (83900.572 MHz), but is 2.7 MHz (or 9.1 km s −1 ) too low for that of CH 3 OD (83903.300 ± 0.032 MHz; Anderson et al 1988). Second, the astronomical frequency at 104874 MHz is also in very good agreement with the laboratory data for HOCN, and, as Turner (1991) notes, a rotational-temperature analysis confirms that this line cannot be HCOOH because the intensity is about a factor of 10 too high (see Figure 1 and Section 3.2.17 in Turner 1991).…”

Section: Identification Of Hocn In Sgr B2mentioning

confidence: 90%

LABORATORY DETECTION OF HOCN AND TENTATIVE IDENTIFICATION IN Sgr B2

Brünken

Gottlieb

McCarthy

et al. 2009

ApJ

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The rotational spectrum of cyanic acid, HOCN, has been detected in the centimeter-wave band in a molecular beam by Fourier transform microwave spectroscopy and in the millimeter-wave band by conventional spectroscopy in a low-pressure laboratory discharge. Spectroscopic constants, including the nitrogen hyperfine coupling constant, derived from 31 a-type transitions between 21 and 360 GHz with J up to 17 and K a 2 allow the spectrum in the only rotational ladders populated in the interstellar gas to be calculated well into the submillimeter-wave band to 1 km s −1 or better in equivalent radial velocity. Four consecutive transitions of HOCN between 83.9 and 146.8 GHz were tentatively identified in published spectral line surveys of Sgr B2(OH). An approximate column density in Sgr B2(OH) of 6 × 10 12 cm −2 implies that the HOCN/ HNCO ratio is about 0.5%. Because HNCO is widely distributed in the interstellar gas, HOCN may be as well.

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Section: Identification Of Hocn In Sgr B2mentioning

confidence: 90%

LABORATORY DETECTION OF HOCN AND TENTATIVE IDENTIFICATION IN Sgr B2

Brünken

Gottlieb

McCarthy

et al. 2009

ApJ

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“…They are based on Pearson et al (2012) with rest frequencies almost entirely from that study. With the use of torsional energies from Lauvergnat et al (2009), we estimate a vibrational correction factor to the partition function of 1.15 at 160 K. For CH 3 OD, we prepared a catalog entry based on Anderson et al (1988), with frequencies updated to the values published in Duan et al (2003). We estimated the partition function to be 11 770 at 150 K and 25 550 at 225 K, taking torsional energies of CH 3 OD in 5 See http://spec.jpl.nasa.gov Anderson et al (1988) into account.…”

Section: Spectroscopic Predictionsmentioning

confidence: 99%

Exploring molecular complexity with ALMA (EMoCA): Deuterated complex organic molecules in Sagittarius B2(N2)

Беллоче

Müller

Garrod

et al. 2016

A&A

200

345

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Context. Deuteration is a powerful tracer of the history of the cold prestellar phase in star-forming regions. Apart from methanol, little is known about deuterium fractionation of complex organic molecules in the interstellar medium, especially in regions forming high-mass stars. Aims. Our goal is to detect deuterated complex organic molecules toward the high mass star-forming region Sagittarius B2 (Sgr B2) and derive the level of deuteration for these molecules. Methods. We use a complete 3-mm spectral line survey performed with the Atacama Large Millimeter/submillimeter Array (ALMA) to search for deuterated complex organic molecules toward the hot molecular core Sgr B2(N2). We constructed population diagrams and integrated intensity maps to fit rotational temperatures and emission sizes for each molecule. Column densities are derived by modeling the full spectrum under the assumption of local thermodynamic equilibrium. We compare the results to predictions of two astrochemical models that treat the deuteration process. Results. We report the detection of CH 2 DCN toward Sgr B2(N2) with a deuteration level of 0.4%, and tentative detections of CH 2 DOH, CH 2 DCH 2 CN, the chiral molecule CH 3 CHDCN, and DC 3 N with levels in the range 0.05%-0.12%. A stringent deuteration upper limit is obtained for CH 3 OD (<0.07%). Upper limits in the range 0.5-1.8% are derived for the three deuterated isotopologues of vinyl cyanide, the four deuterated species of ethanol, and CH 2 DOCHO. Ethyl cyanide is less deuterated than methyl cyanide by at least a factor five. The [CH 2 DOH]/[CH 3 OD] abundance ratio is higher than 1.8. It may still be consistent with the value obtained in Orion KL. Except for methyl cyanide, the measured deuteration levels lie at least a factor four below the predictions of current astrochemical models. The deuteration levels in Sgr B2(N2) are also lower than in Orion KL by a factor of a few up to a factor ten. Conclusions. The discrepancy between the deuteration levels of Sgr B2(N2) and the predictions of chemical models, and the difference between Sgr B2(N2) and Orion KL may both be due to the higher kinetic temperatures that characterize the Galactic center region compared to nearby clouds. Alternatively, they may result from a lower overall abundance of deuterium itself in the Galactic center region by up to a factor ten.

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“…The molecular data for CH 3 OD are taken from Anderson et al (1988). A computer file of the CH 3 OD transitions, provided by Herbst (pers.…”

Section: Deuterated Methanol (Ch 3 Od Ch 2 Doh)mentioning

confidence: 99%

The composition of ices in comet C/1995 O1 (Hale-Bopp) from radio spectroscopy

Crovisier

Bockelée‐Morvan²,

Colom³

et al. 2004

A&A

218

159

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Abstract. From radio spectroscopic observations of comets, more than 22 molecules, radicals and ions, plus several isotopologues, were detected, the majority of them being recently revealed in comets C/1996 B2 (Hyakutake) and C/1995 O1 (Hale-Bopp). Among them, 6 molecules were detected for the first time (Bockelée-Morvan et al. 2000) in the course of a spectral survey conducted at radio wavelengths in comet Hale-Bopp with the CSO, the IRAM 30-m telescope and Plateau de Bure interferometer. In addition, many species were searched for unsuccessfully, some of them with stringent upper limits. We present here a review of these observations and further analysis of their results. This include: (i) confirmed detection of acetaldehyde (CH 3 CHO); (ii) limits on small molecules such as ketene (H 2 CCO) or methanimine (CH 2 NH); (iii) limits on the abundance ratios in homologous series such as HC 5 N/HC 3 N, ethanol/methanol, acetic acid/formic acid; (iv) searches for precursors of key cometary species such as atomic Na and HNC; (v) constraints on more exotic species ranging from water dimer (H 2 O) 2 to glycine; (vi) detection of the H 34 2 S isotopic species and independent observations of HDO and DCN; (vii) limits on several other deuterated species; (viii) limits on several radicals and ions and a tentative detection of the C 2 H radical; (ix) the presence of unidentified lines. Typical abundance upper limits of 2-5 ×10 −4 relative to water are achieved for many species. Better upper limits are obtained for some linear molecules with high dipole moments. But more complex molecules such as dimethyl ether or glycine are poorly constrained. These results should give important clues to the chemical composition of cometary ices, to the formation mechanisms of cometary material, and to the chemical processes which occur in the inner coma.

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The laboratory millimeter- and submillimeter-wave spectrum of CH3OD

Cited by 46 publications

References 0 publications

LABORATORY DETECTION OF HOCN AND TENTATIVE IDENTIFICATION IN Sgr B2

LABORATORY DETECTION OF HOCN AND TENTATIVE IDENTIFICATION IN Sgr B2

Exploring molecular complexity with ALMA (EMoCA): Deuterated complex organic molecules in Sagittarius B2(N2)

The composition of ices in comet C/1995 O1 (Hale-Bopp) from radio spectroscopy

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