Laboratory Characterization and Astrophysical Detection of Vibrationally Excited States of Ethyl Cyanide

Daly, Adam M.; Bermúdez, Celina; López, Alicia; Tercero, B.; Pearson, John C.; Marcelino, N.; Alonso, José L.; Cernicharo, J.

doi:10.1088/0004-637x/768/1/81

Cited by 54 publications

(72 citation statements)

References 36 publications

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“…Taking into account the weakness of the 13 C lines, the derived ratios are compatible with the value of 12 C/ 13 C 35 obtained with the column density ratios between 13 C-HCOOCH 3 and HCOOCH 3 in the ground state (see Carvajal et al 2009;Margulès et al 2010) and agrees quite well with previous results of this ratio in Orion KL (Johansson et al 1984;Blake et al 1987;Demyk et al 2007;Tercero et al 2010;Daly et al 2013;Esplugues et al 2013b). …”

Section: Isotope Ratiossupporting

confidence: 92%

THz spectroscopy and first ISM detection of excited torsional states of¹³C-methyl formate

Haykal¹,

Carvajal²,

Tercero³

et al. 2014

A&A

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Context. An astronomical survey of interstellar molecular clouds needs a previous analysis of the spectra in the microwave and sub-mm energy range of organic molecules to be able to identify them. We obtained very accurate spectroscopic constants in a comprehensive laboratory analysis of rotational spectra. These constants can be used to predict the transitions frequencies very precisely that were not measured in the laboratory. Aims. We present the experimental study and its theoretical analysis for two 13 C-methyl formate isotopologues to detect these two isotopologues for the first time in their excited torsional states, which lie at 130 cm −1 (200 K) in Orion-KL. Methods. New spectra of HCOO 13 CH 3 ( 13 C 2 ) methyl formate were recorded with the mm-and submm-wave spectrometer in Lille from 50 to 940 GHz. A global fit for v t = 0 and 1 was accomplished with the BELGI program to reproduce the experimental spectra with greater accuracy. Results. We analysed 5728 and 2881 new lines for v t = 0 and 1 for HCOO 13 CH 3 . These new lines were globally fitted with 846 previously published lines for v t = 0. In consequence, 52 parameters of the RAM Hamiltonian were accurately determined and the value of the barrier height (V 3 = 369.93168(395) cm −1 ) was improved. We report the detection of the first excited torsional states (v t = 1) in Orion-KL for the 13 C 2 and 13 C 1 methyl formate based on the present analysis and previously published data. We provide column densities, isotopic abundances, and vibrational temperatures for these species. Conclusions. Following this work, accurate prediction can be provided. This permits detecting 135 features of the first excited torsional states of 13 C-methyl formate isotopologues in Orion-KL in the 80−280 GHz frequency range, without missing lines.

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Section: Isotope Ratiossupporting

confidence: 92%

THz spectroscopy and first ISM detection of excited torsional states of¹³C-methyl formate

Haykal¹,

Carvajal²,

Tercero³

et al. 2014

A&A

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“…Daly et al (2013) claimed tentative detections of both deuterated isotopologues of ethyl cyanide with a deuterium fractionation of 2% based on the same survey of Orion KL. No detected transitions are shown in that study, though, and their Table 3 actually reports upper limits for the deuterated species.…”

Section: Deuterated Ethyl Cyanidementioning

confidence: 99%

“…Margulès et al (2009) Daly et al (2013). Daly et al (2013) claimed tentative detections of both deuterated isotopologues of ethyl cyanide with a deuterium fractionation of 2% based on the same survey of Orion KL.…”

Section: Deuterated Ethyl Cyanidementioning

confidence: 99%

“…A few detections or tentative detections of deuterated (complex) organic molecules have been reported toward Orion KL (Gerin et al 1992;Daly et al 2013;Esplugues et al 2013;Neill et al 2013;Coudert et al 2013), but no systematic study of the deuteration of complex organic molecules in high mass star-forming regions has been reported so far.…”

Section: Introductionmentioning

confidence: 99%

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

Беллоче

Müller

Garrod

et al. 2016

A&A

198

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 rotational spectra of deuterated, mono-13 C, and -15 N containing isotopologs of ethyl cyanide (Margulès et al , 2016Richard et al 2012;Heise et al 1974), as well as vibrationally excited ethyl cyanide (Gibb et al 2000b;Heise et al 1981;Mehringer et al 2004;Daly et al 2013;Belloche et al 2013Belloche et al , 2016 have also been investigated and successfully detected in the ISM.…”

Section: Introductionmentioning

confidence: 99%

The millimeter and sub-millimeter rotational spectrum of triple ¹³C-substituted ethyl cyanide

Pienkina

Margulès

Motiyenko

et al. 2017

A&A

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Context.A recently published astronomical detection of all three doubly 13 C-substituted ethyl cyanides toward Sgr B2(N2) motivated us to investigate triple 13 C isotopic species that are expected to be also present in the ISM. Aims. We aim to present an experimental study of the rotational spectrum of triple 13 C-substituted ethyl cyanide, 13 CH 13 3 CH 13 2 CN, in the frequency range 150-990 GHz. We want to use the determined spectroscopic parameters for searching for 13 CH 13 3 CH 13 2 CN in ALMA data. The main objective of this work is to provide accurate frequency predictions to search for this molecule in the Galactic center source Sagittarius B2(N) and to facilitate its detection in space.Methods. The laboratory rotational spectrum of 13 CH 13 3 CH 13 2 CN has been recorded with the Lille's fast DDS solid-state spectrometer between 150 GHz and 990 GHz. Results. More than 4000 rotational transitions were identified in the laboratory. The quantum numbers reach J = 115 and K a = 39. Watson's Hamiltonian in the A and S reductions were used to analyze the spectra. Accurate spectroscopic parameters were determined. The rotational spectra of the 13 C containing species CH 3 CH 2 CN have been assigned, thus allowing the determination of the rotational and centrifugal distortion constants

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Laboratory Characterization and Astrophysical Detection of Vibrationally Excited States of Ethyl Cyanide

Cited by 54 publications

References 36 publications

THz spectroscopy and first ISM detection of excited torsional states of¹³C-methyl formate

THz spectroscopy and first ISM detection of excited torsional states of¹³C-methyl formate

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

The millimeter and sub-millimeter rotational spectrum of triple ¹³C-substituted ethyl cyanide

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Laboratory Characterization and Astrophysical Detection of Vibrationally Excited States of Ethyl Cyanide

Cited by 54 publications

References 36 publications

THz spectroscopy and first ISM detection of excited torsional states of13C-methyl formate

THz spectroscopy and first ISM detection of excited torsional states of13C-methyl formate

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

The millimeter and sub-millimeter rotational spectrum of triple 13C-substituted ethyl cyanide

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Product

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THz spectroscopy and first ISM detection of excited torsional states of¹³C-methyl formate

THz spectroscopy and first ISM detection of excited torsional states of¹³C-methyl formate

The millimeter and sub-millimeter rotational spectrum of triple ¹³C-substituted ethyl cyanide