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Cabezas C, Tercero B, Agúndez M, Marcelino N, Pardo JR, de Vicente P, Cernicharo J. Cumulene carbenes in TMC-1: Astronomical discovery of l-H 2C 5 ★. Astron Astrophys 2021; 650:L9. [PMID: 34334798 PMCID: PMC7611420 DOI: 10.1051/0004-6361/202141274] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We report the first detection in space of the cumulene carbon chain l-H2C5. A total of eleven rotational transitions, with Jup = 7-10 and Ka = 0 and 1, were detected in TMC-1 in the 31.0-50.4 GHz range using the Yebes 40m radio telescope. We derive a column density of (1.8±0.5)×1010 cm-2. In addition, we report observations of other cumulene carbenes detected previously in TMC-1, to compare their abundances with the newly detected cumulene carbene chain. We find that l-H2C5 is ~4.0 times less abundant than the larger cumulene carbene l-H2C6, while it is ~300 and ~500 times less abundant than the shorter chains l-H2C3 and l-H2C4. We discuss the most likely gas-phase chemical routes to these cumulenes in TMC-1 and stress that chemical kinetics studies able to distinguish between different isomers are needed to shed light on the chemistry of C n H2 isomers with n > 3.
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Affiliation(s)
- C. Cabezas
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - B. Tercero
- Observatorio Astronómico Nacional (IGN), C/ Alfonso XII, 3, 28014, Madrid, Spain
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - M. Agúndez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - N. Marcelino
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - J. R. Pardo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - P. de Vicente
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J. Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
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Agúndez M, Marcelino N, Tercero B, Cabezas C, de Vicente P, Cernicharo J. O-bearing complex organic molecules at the cyanopolyyne peak of TMC-1: detection of C 2H 3CHO, C 2H 3OH, HCOOCH 3, and CH 3OCH 3. Astron Astrophys 2021; 649:L4. [PMID: 34334796 PMCID: PMC7611417 DOI: 10.1051/0004-6361/202140978] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We report the detection of the oxygen-bearing complex organic molecules propenal (C2H3CHO), vinyl alcohol (C2H3OH), methyl formate (HCOOCH3), and dimethyl ether (CH3OCH3) toward the cyanopolyyne peak of the starless core TMC-1. These molecules are detected through several emission lines in a deep Q-band line survey of TMC-1 carried out with the Yebes 40m telescope. These observations reveal that the cyanopolyyne peak of TMC-1, which is the prototype of cold dark cloud rich in carbon chains, contains also O-bearing complex organic molecules like HCOOCH3 and CH3OCH3, which have been previously seen in a handful of cold interstellar clouds. In addition, this is the first secure detection of C2H3OH in space and the first time that C2H3CHO and C2H3OH are detected in a cold environment, adding new pieces in the puzzle of complex organic molecules in cold sources. We derive column densities of (2.2 ± 0.3) × 1011 cm™2, (2.5 ± 0.5) × 1012 cm-2, (1.1 ± 0.2) × 1012 cm-2, and (2.5 ± 0.7) × 1012 cm-2 for C2H3CHO, C2H3OH, HCOOCH3, and CH3OCH3, respectively. Interestingly, C2H3OH has an abundance similar to that of its well known isomer acetaldehyde (CH3CHO), with C2H3OH/CH3CHO ~ 1 at the cyanopolyyne peak. We discuss potential formation routes to these molecules and recognize that further experimental, theoretical, and astronomical studies are needed to elucidate the true mechanism of formation of these O-bearing complex organic molecules in cold interstellar sources.
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Affiliation(s)
- M. Agúndez
- Instituto de Física Fundamental, CSIC, Calle Serrano 123, E-28006 Madrid, Spain
| | - N. Marcelino
- Instituto de Física Fundamental, CSIC, Calle Serrano 123, E-28006 Madrid, Spain
| | - B. Tercero
- Observatorio Astronómico Nacional, IGN, Calle Alfonso XII 3, E-28014 Madrid, Spain
- Observatorio de Yebes, IGN, Cerro de la Palera s/n, E-19141 Yebes, Guadalajara, Spain
| | - C. Cabezas
- Instituto de Física Fundamental, CSIC, Calle Serrano 123, E-28006 Madrid, Spain
| | - P. de Vicente
- Observatorio de Yebes, IGN, Cerro de la Palera s/n, E-19141 Yebes, Guadalajara, Spain
| | - J. Cernicharo
- Instituto de Física Fundamental, CSIC, Calle Serrano 123, E-28006 Madrid, Spain
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Agúndez M, Roueff E, Cabezas C, Cernicharo J, Marcelino N. First detection of doubly deuterated methyl acetylene (CHD 2CCH and CH 2DCCD) ★. Astron Astrophys 2021; 649:A171. [PMID: 34334795 PMCID: PMC7611416 DOI: 10.1051/0004-6361/202140843] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We report the first detection in space of the two doubly deuterated isotopologues of methyl acetylene. The species CHD2CCH and CH2DCCD were identified in the dense core L483 through nine and eight, respectively, rotational lines in the 72-116 GHz range using the IRAM 30m telescope. The astronomical frequencies observed here were combined with laboratory frequencies from the literature measured in the 29-47 GHz range to derive more accurate spectroscopic parameters for the two isotopologues. We derive beam-averaged column densities of (2.7 ± 0.5) × 1012 cm-2 for CHD2CCH and (2.2 ± 0.4) × 1012 cm-2 for CH2DCCD, which translate to abundance ratios CH3CCH/CHD2CCH = 34 ± 10 and CH3CCH/CH2DCCD = 42 ± 13. The doubly deuterated isotopologues of methyl acetylene are only a few times less abundant than the singly deuterated ones, concretely around 2.4 times less abundant than CH3CCD. The abundances of the different deuterated isotopologues with respect to CH3CCH are reasonably accounted for by a gas-phase chemical model in which deuteration occurs from the precursor ions C3H6D+ and C3H5D+, when the ortho-to-para ratio of molecular hydrogen is sufficiently low. This points to gas-phase chemical reactions, rather than grain-surface processes, as responsible for the formation and deuterium fractionation of CH3CCH in L483. The abundance ratios CH2DCCH/CH3CCD = 3.0 ± 0.9 and CHD2CCH/CH2DCCD = 1.25 ± 0.37 observed in L483 are consistent with the statistically expected values of three and one, respectively, with the slight overabundance of CHD2CCH compared to CH2DCCD being well explained by the chemical model.
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Affiliation(s)
- M. Agúndez
- Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006 Madrid, Spain
| | - E. Roueff
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Université, F-92190, Meudon, France
| | - C. Cabezas
- Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006 Madrid, Spain
| | - J. Cernicharo
- Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006 Madrid, Spain
| | - N. Marcelino
- Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006 Madrid, Spain
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Cernicharo J, Cabezas C, Agúndez M, Tercero B, Pardo JR, Marcelino N, Gallego J, Tercero F, López-Pérez J, de Vicente P. TMC-1, the starless core sulfur factory: Discovery of NCS, HCCS, H 2CCS, H 2CCCS, and C 4S and detection of C 5S. Astron Astrophys 2021; 648:L3. [PMID: 33850333 PMCID: PMC7610586 DOI: 10.1051/0004-6361/202140642] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We report the detection of the sulfur-bearing species NCS, HCCS, H2CCS, H2CCCS, and C4S for the first time in space. These molecules were found towards TMC-1 through the observation of several lines for each species. We also report the detection of C5S for the first time in a cold cloud through the observation of five lines in the 31-50 GHz range. The derived column densities are N(NCS) = (7.8±0.6)×1011 cm-2, N(HCCS) = (6.8±0.6)×1011 cm-2, N(H2CCS) = (7.8±0.8)×1011 cm-2, N(H2CCCS) = (3.7±0.4)×1011 cm-2, N(C4S) = (3.8±0.4)×1010 cm-2, and N(C5S) = (5.0±1.0)×1010 cm-2. The observed abundance ratio between C3S and C4S is 340, that is to say a factor of approximately one hundred larger than the corresponding value for CCS and C3S. The observational results are compared with a state-of-the-art chemical model, which is only partially successful in reproducing the observed abundances. These detections underline the need to improve chemical networks dealing with S-bearing species.
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Affiliation(s)
- J. Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - C. Cabezas
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - M. Agúndez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - B. Tercero
- Observatorio Astronómico Nacional (IGN), C/ Alfonso XII, 3, 28014, Madrid, Spain
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J. R. Pardo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - N. Marcelino
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - J.D. Gallego
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - F. Tercero
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J.A. López-Pérez
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - P. de Vicente
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
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Cernicharo J, Agúndez M, Cabezas C, Marcelino N, Tercero B, Pardo JR, Gallego JD, Tercero F, López-Pérez JA, de Vicente P. Discovery of CH 2CHCCH and detection of HCCN, HC 4N, CH 3CH 2CN, and, tentatively, CH 3CH 2CCH in TMC-1. Astron Astrophys 2021; 647:L2. [PMID: 33833468 PMCID: PMC7610549 DOI: 10.1051/0004-6361/202140434] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We present the discovery in TMC-1 of vinyl acetylene, CH2CHCCH, and the detection, for the first time in a cold dark cloud, of HCCN, HC4N, and CH3CH2CN. A tentative detection of CH3CH2CCH is also reported. The column density of vinyl acetylene is (1.2±0.2)×1013 cm-2, which makes it one of the most abundant closed-shell hydrocarbons detected in TMC-1. Its abundance is only three times lower than that of propylene, CH3CHCH2. The column densities derived for HCCN and HC4N are (4.4±0.4)×1011 cm-2 and (3.7±0.4)×1011 cm-2, respectively. Hence, the HCCN/HC4N abundance ratio is 1.2±0.3. For ethyl cyanide we derive a column density of (1.1 ±0.3)×1011 cm-2. These results are compared with a state-of-the-art chemical model of TMC-1, which is able to account for the observed abundances of these molecules through gas-phase chemical routes.
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Affiliation(s)
- J Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - M Agúndez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - C Cabezas
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - N Marcelino
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - B Tercero
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
- Observatorio Astronómico Nacional (IGN), C/ Alfonso XII, 3, 28014, Madrid, Spain
| | - J R Pardo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - J D Gallego
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - F Tercero
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J A López-Pérez
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - P de Vicente
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
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Cernicharo J, Cabezas C, Agúndez M, Tercero B, Marcelino N, Pardo JR, Tercero F, Gallego J, López-Pérez J, deVicente P. Discovery of allenyl acetylene, H 2CCCHCCH, in TMC-1. A study of the isomers of C 5H 4. Astron Astrophys 2021; 647:L3. [PMID: 33850332 PMCID: PMC7610584 DOI: 10.1051/0004-6361/202140482] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We present the discovery in TMC-1 of allenyl acetylene, H2CCCHCCH, through the observation of nineteen lines with a signal-to-noise ratio ~4-15. For this species, we derived a rotational temperature of 7±1K and a column density of 1.2±0.2×1013 cm-2. The other well known isomer of this molecule, methyl diacetylene (CH3C4H), has also been observed and we derived a similar rotational temperature, Tr=7.0±0.3 K, and a column density for its two states (A and E) of 6.5±0.3×1012 cm-2. Hence, allenyl acetylene and methyl diacetylene have a similar abundance. Remarkably, their abundances are close to that of vinyl acetylene (CH2CHCCH). We also searched for the other isomer of C5H4, HCCCH2CCH (1.4-Pentadiyne), but only a3σ upper limit of 2.5×1012 cm-2 to the column density can be established. These results have been compared to state-of-the-art chemical models for TMC-1, indicating the important role of these hydrocarbons in its chemistry. The rotational parameters of allenyl acetylene have been improved by fitting the existing laboratory data together with the frequencies of the transitions observed in TMC-1.
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Affiliation(s)
- J. Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - C. Cabezas
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - M. Agúndez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - B. Tercero
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
- Observatorio Astronómico Nacional (OAN, IGN), Madrid, Spain
| | - N. Marcelino
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - J. R. Pardo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - F. Tercero
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J.D. Gallego
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J.A. López-Pérez
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - P. deVicente
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
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Agúndez M, Cabezas C, Tercero B, Marcelino N, Gallego JD, de Vicente P, Cernicharo J. Discovery of the propargyl radical (CH 2CCH) in TMC-1: one of the most abundant radicals ever found and a key species for cyclization to benzene in cold dark clouds. Astron Astrophys 2021; 647:L10. [PMID: 33850331 PMCID: PMC7610583 DOI: 10.1051/0004-6361/202140553] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We present the first identification in interstellar space of the propargyl radical (CH2CCH). This species was observed in the cold dark cloud TMC-1 using the Yebes 40m telescope. The six strongest hyperfine components of the 20,2-10,1 rotational transition, lying at 37.46 GHz, were detected with signal-to-noise ratios in the range 4.6-12.3 σ. We derive a column density of 8.7 × 1013 cm-2 for CH2CCH, which translates to a fractional abundance relative to H2 of 8.7 × 10-9. This radical has a similar abundance to methyl acetylene, with an abundance ratio CH2CCH/CH3CCH close to one. The propargyl radical is thus one of the most abundant radicals detected in TMC-1, and it is probably the most abundant organic radical with a certain chemical complexity ever found in a cold dark cloud. We constructed a gas-phase chemical model and find calculated abundances that agree with, or fall two orders of magnitude below, the observed value depending on the poorly constrained low-temperature reactivity of CH2CCH with neutral atoms. According to the chemical model, the propargyl radical is essentially formed by the C + C2H4 reaction and by the dissociative recombination of C3Hn + ions with n = 4-6. The propargyl radical is believed to control the synthesis of the first aromatic ring in combustion processes, and it probably plays a key role in the synthesis of large organic molecules and cyclization processes to benzene in cold dark clouds.
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Affiliation(s)
- M. Agúndez
- Instituto de Física Fundamental, CSIC, Calle Serrano 123, E-28006 Madrid, Spain
| | - C. Cabezas
- Instituto de Física Fundamental, CSIC, Calle Serrano 123, E-28006 Madrid, Spain
| | - B. Tercero
- Observatorio Astronómico Nacional, IGN, Calle Alfonso XII 3, E-28014 Madrid, Spain
- Observatorio de Yebes, IGN, Cerro de la Palera s/n, E-19141 Yebes, Guadalajara, Spain
| | - N. Marcelino
- Instituto de Física Fundamental, CSIC, Calle Serrano 123, E-28006 Madrid, Spain
| | - J. D. Gallego
- Observatorio de Yebes, IGN, Cerro de la Palera s/n, E-19141 Yebes, Guadalajara, Spain
| | - P. de Vicente
- Observatorio de Yebes, IGN, Cerro de la Palera s/n, E-19141 Yebes, Guadalajara, Spain
| | - J. Cernicharo
- Instituto de Física Fundamental, CSIC, Calle Serrano 123, E-28006 Madrid, Spain
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Cernicharo J, Cabezas C, Bailleux S, Margulès L, Motiyenko R, Zou L, Endo Y, Bermúdez C, Agúndez M, Marcelino N, Lefloch B, Tercero B, de Vicente P. Discovery of the acetyl cation, CH 3CO +, in space and in the laboratory. Astron Astrophys 2021; 646:L7. [PMID: 33828331 PMCID: PMC7610537 DOI: 10.1051/0004-6361/202040076] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Using the Yebes 40m and IRAM 30m radiotelescopes, we detected two series of harmonically related lines in space that can be fitted to a symmetric rotor. The lines have been seen towards the cold dense cores TMC-1, L483, L1527, and L1544. High level of theory ab initio calculations indicate that the best possible candidate is the acetyl cation, CH3CO+, which is the most stable product resulting from the protonation of ketene. We have produced this species in the laboratory and observed its rotational transitions Ju = 10 up to Ju = 27. Hence, we report the discovery of CH3CO+ in space based on our observations, theoretical calculations, and laboratory experiments. The derived rotational and distortion constants allow us to predict the spectrum of CH3CO+ with high accuracy up to 500 GHz. We derive an abundance ratio N(H2CCO)/N(CH3CO+)~44. The high abundance of the protonated form of H2CCO is due to the high proton affinity of the neutral species. The other isomer, H2CCOH+, is found to be 178.9 kJ mol-1 above CH3CO+. The observed intensity ratio between the K=0 and K=1 lines, ~2.2, strongly suggests that the A and E symmetry states have suffered interconversion processes due to collisions with H and/or H2, or during their formation through the reaction of H 3 + with H2CCO.
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Affiliation(s)
- J Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - C Cabezas
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - S Bailleux
- Univ. Lille, CNRS, UMR 8523 - PhLAM - Physique des Lasers Atomes et Molécules, 59000 Lille, France
| | - L Margulès
- Univ. Lille, CNRS, UMR 8523 - PhLAM - Physique des Lasers Atomes et Molécules, 59000 Lille, France
| | - R Motiyenko
- Univ. Lille, CNRS, UMR 8523 - PhLAM - Physique des Lasers Atomes et Molécules, 59000 Lille, France
| | - L Zou
- Univ. Lille, CNRS, UMR 8523 - PhLAM - Physique des Lasers Atomes et Molécules, 59000 Lille, France
| | - Y Endo
- Department of Applied Chemistry, Science Building II, National Chiao Tung University, 1001 Ta-Hsueh Rd., Hsinchu 30010, Taiwan
| | - C Bermúdez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - M Agúndez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - N Marcelino
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - B Lefloch
- CNRS, IPAG, Univ. Grenoble Alpes, F-38000 Grenoble, France
| | - B Tercero
- Observatorio Astronómico Nacional (IGN), C/ Alfonso XII, 3, 28014, Madrid, Spain
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - P de Vicente
- Observatorio Astronómico Nacional (IGN), C/ Alfonso XII, 3, 28014, Madrid, Spain
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Jabri A, Tercero B, Margulès L, Motiyenko RA, Alekseev EA, Kleiner I, Cernicharo J, Guillemin JC. Rotational spectroscopic study of S-methyl thioformate: A global laboratory analysis of ground and excited torsional states up to 660 GHz. Astron Astrophys 2020; 644:A102. [PMID: 33594292 PMCID: PMC7116753 DOI: 10.1051/0004-6361/202038200] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
CONTEXT S-methyl thioformate CH3SC(O)H is a monosulfur derivative of methyl formate, a relatively abundant component of the interstellar medium (ISM). S-methyl thioformate being, thermodynamically, the most stable isomer, it can be reasonably proposed for detection in the ISM. AIMS This work aims to experimentally study and theoretically analyze the ground and first torsional excited states for CH3SC(O)H in a large spectral range for astrophysical use. METHODS S-methyl thioformate was synthesized as a result of a reaction of methyl mercaptan with acetic-formic anhydride. The millimeter-wave spectrum was then recorded for the first time from 150 to 660 GHz with the solid-state spectrometer located at Lille. RESULTS A set of 3545 lines is determined and combined with 54 previously measured lines in the microwave region, belonging to ground state ν t = 0 as well as 1391 transitions in the first excited state of torsion ν 18 = 1. Some 164 lines were also assigned to ν 18 = 2 for the A-species. A global fit was performed using the BELGI-Cs code taking into account the large splitting of A and E lines due to methyl internal rotation motion with a relatively low barrier, V3 = 127.4846(15) cm-1. CONCLUSIONS Using our spectroscopy work, a deep search of S-methyl thioformate was carried out in the IRAM 30m and ALMA data of different high-mass star-forming regions (Orion KL and Sgr B2). We derived an upper limit to the CH3SC(O)H column density in these regions.
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Affiliation(s)
- A Jabri
- Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), UMR CNRS 7583, Université Paris-Est-Créteil, Université de Paris, Institut Pierre Simon Laplace (IPSL), 61 av. du Général de Gaulle, 94010 Créteil, France
| | - B Tercero
- Observatorio Astronómico Nacional (OAN-IGN). Calle Alfonso XII, 3, 28014 Madrid, Spain
- Observatorio de Yebes (IGN). Cerro de la Palera s/n, 19141 Yebes, Guadalajara, Spain
| | - L Margulès
- Univ. Lille, CNRS, UMR 8523 - PhLAM - Physique des Lasers Atomes et Molécules, 59000 Lille, France
| | - R A Motiyenko
- Univ. Lille, CNRS, UMR 8523 - PhLAM - Physique des Lasers Atomes et Molécules, 59000 Lille, France
| | - E A Alekseev
- Radiospectrometry Department, Institute of Radio Astronomy of NASU, Kharkov, Ukraine
| | - I Kleiner
- Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), UMR CNRS 7583, Université Paris-Est-Créteil, Université de Paris, Institut Pierre Simon Laplace (IPSL), 61 av. du Général de Gaulle, 94010 Créteil, France
| | - J Cernicharo
- Instituto de Física Fundamental (IFF-CSIC). Calle Serrano 123, 28006 Madrid, Spain
| | - J-C Guillemin
- Univ. Rennes, Ecole Nationale Supérieure de Chimie de Rennes, CNRS, ISCR-UMR 6226, 35000 Rennes, France
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Marcelino N, Agúndez M, Tercero B, Cabezas C, Bermúdez C, Gallego JD, de Vicente P, Cernicharo J. Tentative detection of HC 5NH + in TMC-1. Astron Astrophys 2020; 643:L6. [PMID: 33239826 PMCID: PMC7116411 DOI: 10.1051/0004-6361/202039251] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Using the Yebes 40m radio telescope, we report the detection of a series of seven lines harmonically related with a rotational constant B 0=1295.81581 ± 0.00026 MHz and a distortion constant D 0 = 27.3 ± 0.5 Hz towards the cold dense cloud TMC-1. Ab initio calculations indicate that the best possible candidates are the cations HC5NH+ and NC4NH+. From a comparison between calculated and observed rotational constants and other arguments based on proton affinities and dipole moments, we conclude that the best candidate for a carrier of the observed lines is the protonated cyanodiacetylene cation, HC5NH+. The HC5N/HC5NH+ ratio derived in TMC-1 is 240, which is very similar to the HC3N/HC3NH+ ratio. Results are discussed in the framework of a chemical model for protonated molecules in cold dense clouds.
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Affiliation(s)
- N Marcelino
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/Serrano 121, 28006 Madrid, Spain
| | - M Agúndez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/Serrano 121, 28006 Madrid, Spain
| | - B Tercero
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
- Observatorio Astronómico Nacional (IGN), C/Alfonso XII, 3, 28014, Madrid, Spain
| | - C Cabezas
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/Serrano 121, 28006 Madrid, Spain
| | - C Bermúdez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/Serrano 121, 28006 Madrid, Spain
| | - J D Gallego
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - P de Vicente
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/Serrano 121, 28006 Madrid, Spain
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11
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Fonfría JP, Montiel EJ, Cernicharo J, DeWitt CN, Richter MJ. Detection of infrared fluorescence of carbon dioxide in R Leonis with SOFIA/EXES. Astron Astrophys 2020; 643:L15. [PMID: 33239827 PMCID: PMC7116412 DOI: 10.1051/0004-6361/202039547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We report on the detection of hot CO2 in the O-rich AGB star R Leo based on high spectral resolution observations in the range 12.8 - 14.3 μm carried out with the Echelon-cross-Echelle Spectrograph (EXES) mounted on the Stratospheric Observatory for Infrared Astronomy (SOFIA). We have found ≃ 240 CO2 emission lines in several vibrational bands. These detections were possible thanks to a favorable Doppler shift that allowed us to avoid contamination by telluric CO2 features. The highest excitation lines involve levels at an energy of ≃ 7000 K. The detected lines are narrow (average deconvolved width ≃ 2.5 km s-1) and weak (usually ≲ 10% the continuum). A ro-vibrational diagram shows that there are three different populations, warm, hot, and very hot, with rotational temperatures of ≃ 550, 1150, and 1600 K, respectively. From this diagram, we derive a lower limit for the column density of ≃ 2.2 × 1016 cm-2. Further calculations based on a model of the R Leo envelope suggest that the total column density can be as large as 7 × 1017 cm -2 and the abundance with respect to H2 - 2.5 × 10-5. The detected lines are probably formed due to de-excitation of CO2 molecules from high energy vibrational states, which are essentially populated by the strong R Leo continuum at 2.7 and 4.2 μm.
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Affiliation(s)
- J P Fonfría
- Molecular Astrophysics Group, Instituto de Física Fundamental, IFF-CSIC, C/ Serrano, 123, 28006, Madrid (Spain)
| | - E J Montiel
- SOFIA-USRA, NASA Ames Research Center, MS 232-12, Moffett Field, CA 94035 (USA)
| | - J Cernicharo
- Molecular Astrophysics Group, Instituto de Física Fundamental, IFF-CSIC, C/ Serrano, 123, 28006, Madrid (Spain)
| | - C N DeWitt
- SOFIA-USRA, NASA Ames Research Center, MS 232-12, Moffett Field, CA 94035 (USA)
| | - M J Richter
- Physics Dept. - UC Davis, One Shields Ave., Davis, CA 95616 (USA)
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Cernicharo J, Marcelino N, Agúndez M, Bermúdez C, Cabezas C, Tercero B, Pardo JR. Discovery of HC 4NC in TMC-1: A study of the isomers of HC 3N, HC 5N, and HC 7N. Astron Astrophys 2020; 642:L8. [PMID: 33239824 PMCID: PMC7116413 DOI: 10.1051/0004-6361/202039274] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We present a study of the isocyano isomers of the cyanopolyynes HC3N, HC5N, and HC7N in TMC-1 and IRC+10216 carried out with the Yebes 40m radio telescope. This study has enabled us to report the detection, for the first time in space, of HCCCCNC in TMC-1 and to give upper limits for HC6NC in the same source. In addition, the deuterated isotopologues of HCCNC and HNCCC were detected, along with all 13C substitutions of HCCNC, also for the first time in space. The abundance ratios of HC3N and HC5N, with their isomers, are very different in TMC-1 and IRC+10216, namely, N(HC5N)/N(HC4NC) is ~300 and ≥2100, respectively. We discuss the chemistry of the metastable isomers of cyanopolyynes in terms of the most likely formation pathways and by comparing observational abundance ratios between different sources.
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Affiliation(s)
- J. Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - N. Marcelino
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - M. Agúndez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - C. Bermúdez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - C. Cabezas
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - B. Tercero
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
- Observatorio Astronómico Nacional (OAN, IGN), Madrid, Spain
| | - J. R. Pardo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
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Cernicharo J, Marcelino N, Agúndez M, Endo Y, Cabezas C, Bermúdez C, Tercero B, de Vicente P. Discovery of HC 3O + in space: The chemistry of O-bearing species in TMC-1. Astron Astrophys 2020; 642:L17. [PMID: 33239825 PMCID: PMC7116414 DOI: 10.1051/0004-6361/202039351] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Using the Yebes 40m and IRAM 30m radio telescopes, we detected a series of harmonically related lines with a rotational constant B 0=4460.590±0.001 MHz and a distortion constant D 0=0.511 ±0.005 kHz towards the cold dense core TMC-1. High-level-of-theory ab initio calculations indicate that the best possible candidate is protonated tricarbon monoxide, HC3O+. We have succeeded in producing this species in the laboratory and observed its J u -J l = 2-1 and 3-2 rotational transitions. Hence, we report the discovery of HC3O+ in space based on our observations, theoretical calculations, and laboratory experiments. We derive an abundance ratio N(C3O)/N(HC3O+)~7. The high abundance of the protonated form of C3O is due to the high proton affinity of the neutral species. The chemistry of O-bearing species is modelled, and predictions are compared to the derived abundances from our data for the most prominent O-bearing species in TMC-1.
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Affiliation(s)
- J Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - N Marcelino
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - M Agúndez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - Y Endo
- Department of Applied Chemistry, Science Building II, National Chiao Tung University, 1001 Ta-Hsueh Rd., Hsinchu 30010, Taiwan
| | - C Cabezas
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - C Bermúdez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - B Tercero
- Observatorio Astronómico Nacional (IGN), C/ Alfonso XII, 3, 28014, Madrid, Spain
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - P de Vicente
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
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Cernicharo J, Marcelino N, Pardo JR, Agúndez M, Tercero B, de Vicente P, Cabezas C, Bermúdez C. Interstellar nitrile anions: Detection of C 3N - and C 5N - in TMC-1 . Astron Astrophys 2020; 641:L9. [PMID: 33173234 PMCID: PMC7116340 DOI: 10.1051/0004-6361/202039231] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We report on the first detection of C3N- and C5N- towards the cold dark core TMC-1 in the Taurus region, using the Yebes 40 m telescope. The observed C3N/C3N- and C5N/C5N- abundance ratios are ~140 and ~2, respectively; that is similar to those found in the circumstellar envelope of the carbon-rich star IRC +10216. Although the formation mechanisms for the neutrals are different in interstellar (ion-neutral reactions) and circumstellar clouds (photodissociation and radical-neutral reactions), the similarity of the C3N/C3N- and C5N/C5N- abundance ratios strongly suggests a common chemical path for the formation of these anions in interstellar and circumstellar clouds. We discuss the role of radiative electronic attachment, reactions between N atoms and carbon chain anions C n -, and that of H- reactions with HC3N and HC5N as possible routes to form C n N-. The detection of C5N- in TMC-1 gives strong support for assigning to this anion the lines found in IRC +10216, as it excludes the possibility of a metal-bearing species, or a vibrationally excited state. New sets of rotational parameters have been derived from the observed frequencies in TMC-1 and IRC +10216 for C5N- and the neutral radical C5N.
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Affiliation(s)
- J Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - N Marcelino
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - J R Pardo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - M Agúndez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - B Tercero
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
- Observatorio Astronómico Nacional (IGN), C/ Alfonso XII, 3, 28014, Madrid, Spain
| | - P de Vicente
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - C Cabezas
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - C Bermúdez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
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Cabezas C, Bermúdez C, Tercero B, Cernicharo J. The millimeter-wave spectrum and astronomical search for ethyl methyl sulfide. Astron Astrophys 2020; 639:A129. [PMID: 32724240 PMCID: PMC7115819 DOI: 10.1051/0004-6361/202038177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
CONTEXT Sulfur-containing molecules constitute only 8% of the molecules observed in the interstellar medium (ISM), in spite of the fact that sulfur has been shown to be an abundant element in the ISM. In order to understand the chemical behavior of the ISM and specific cases like the missing sulfur reservoir, a detailed chemical molecular composition in the ISM must be mapped out. AIMS Our goal is to investigate the rotational spectrum of ethyl methyl sulfide, CH3CH2SCH3, which ms to be a potential candidate for observation in the ISM since the simpler analogs, CH3SH and CH3CH2SH, have already been detected. Rotational spectrum of ethyl methyl sulfide has been observed before, but its experimental rotational parameters are not precise enough to allow its detection in the ISM. METHODS The rotational spectrum of ethyl methyl sulfide in the frequency range 72-116.5 GHz was measured using a broadband millimeter-wave spectrometer based on radio astronomy receivers with fast Fourier transform backends. The spectral searches and identification of the vibrational excited states of ethyl methyl sulfide was supported by high-level ab initio calculations on the harmonic and anharmonic force fields. RESULTS The rotational spectra for the trans and gauche conformers of ethyl methyl sulfide was analyzed, and a total of 172 and 259 rotational transitions were observed for each one, respectively. The observation of A - E internal rotation splittings allowed the experimental determination of the V 3 hindered internal rotation barrier height for both trans and gauche species. In addition, the vibrational excited states, resulting from the lowest frequency vibrational mode ν 30 were identified for both conformers. The new experimental rotational parameters were employed to search for ethyl methyl sulfide in the warm and cold molecular clouds Orion KL, Sgr B2(N), B1-b and TMC-1, using the spectral surveys captured by IRAM 30 m at 3 mm and 2 mm.
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Affiliation(s)
- C. Cabezas
- Instituto de Física Fundamental (IFF-CSIC). Group of Molecular Astrophysics, C/Serrano 123, 28006 Madrid, Spain
| | - C. Bermúdez
- Instituto de Física Fundamental (IFF-CSIC). Group of Molecular Astrophysics, C/Serrano 123, 28006 Madrid, Spain
| | - B. Tercero
- Observatorio de Yebes (IGN), Cerro de la Palera s/n, 19141 Yebes, Guadalajara, Spain
- Observatorio Astronómico Nacional (OAN-IGN), C/Alfonso XII 3, 28014 Madrid, Spain
| | - J. Cernicharo
- Instituto de Física Fundamental (IFF-CSIC). Group of Molecular Astrophysics, C/Serrano 123, 28006 Madrid, Spain
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Cernicharo J, Cabezas C, Pardo JR, Agúndez M, Bermúdez C, Velilla-Prieto L, Tercero F, López-Pérez JA, Gallego JD, Fonfría JP, Quintana-Lacaci G, Guélin M, Endo Y. Discovery of two new magnesium-bearing species in IRC+10216: MgC 3N and MgC 4H. Astron Astrophys 2019; 630:L2. [PMID: 31579315 PMCID: PMC6774763 DOI: 10.1051/0004-6361/201936372] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We report on the detection of two series of harmonically related doublets in IRC +10216. From the observed frequencies, the rotational constant of the first series is B = 1380.888 MHz and that of the second series is B = 1381.512 MHz. The two series correspond to two species with a 2Σ electronic ground state. After considering all possible candidates, and based on quantum chemical calculations, the first series is assigned to MgC3N and the second to MgC4H. For the latter species, optical spectroscopy measurements support its identification. Unlike diatomic metal-containing molecules, the line profiles of the two new molecules indicate that they are formed in the outer layers of the envelope, as occurs for MgNC and other polyatomic metal-cyanides. We also confirm the detection of MgCCH that was previously reported from the observation of two doublets. The relative abundance of MgC3N with respect to MgNC is close to one while that of MgC4H relative to MgCCH is about ten. The synthesis of these magnesium cyanides and acetylides in IRC +10216 can be explained in terms of a two-step process initiated by the radiative association of Mg+ with large cyanopolyynes and polyynes followed by the dissociative recombination of the ionic complexes.
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Affiliation(s)
- J. Cernicharo
- Grupo de Astrofísica Molecular. Instituto de Física Fundamental (IFF-CSIC). C/Serrano 121, 28006 Madrid, Spain
| | - C. Cabezas
- Grupo de Astrofísica Molecular. Instituto de Física Fundamental (IFF-CSIC). C/Serrano 121, 28006 Madrid, Spain
| | - J. R. Pardo
- Grupo de Astrofísica Molecular. Instituto de Física Fundamental (IFF-CSIC). C/Serrano 121, 28006 Madrid, Spain
| | - M. Agúndez
- Grupo de Astrofísica Molecular. Instituto de Física Fundamental (IFF-CSIC). C/Serrano 121, 28006 Madrid, Spain
| | - C. Bermúdez
- Grupo de Astrofísica Molecular. Instituto de Física Fundamental (IFF-CSIC). C/Serrano 121, 28006 Madrid, Spain
| | - L. Velilla-Prieto
- Grupo de Astrofísica Molecular. Instituto de Física Fundamental (IFF-CSIC). C/Serrano 121, 28006 Madrid, Spain
- Department of Space, Earth and Environment, Chalmers University of Technology, Onsala Space Observatory, 439 92 Onsala, Sweden
| | - F. Tercero
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J. A. López-Pérez
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J. D. Gallego
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J. P. Fonfría
- Grupo de Astrofísica Molecular. Instituto de Física Fundamental (IFF-CSIC). C/Serrano 121, 28006 Madrid, Spain
| | - G. Quintana-Lacaci
- Grupo de Astrofísica Molecular. Instituto de Física Fundamental (IFF-CSIC). C/Serrano 121, 28006 Madrid, Spain
| | - M. Guélin
- Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, F-38406, Saint Martin d’Hères, France
| | - Y. Endo
- Department of Applied Chemistry, Science Building II, National Chiao Tung University, 1001 Ta-Hsueh Rd., Hsinchu 30010, Taiwan
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Cabezas C, Bermúdez C, Gallego JD, Tercero B, Hernández JM, Tanarro I, Herrero VJ, Doménech JL, Cernicharo J. The millimeter-wave spectrum and astronomical search of succinonitrile and its vibrational excited states ★. Astron Astrophys 2019; 629:A35. [PMID: 31485081 PMCID: PMC6726483 DOI: 10.1051/0004-6361/201935899] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
CONTEXT Dinitriles with a saturated hydrocarbon skeleton and a -C≡N group at each end can have large electric dipole moments. Their formation can be related to highly reactive radicals such as CH2CN, C2N or CN. Thus, these saturated dinitriles are potential candidates to be observed in the ISM. AIMS Our goal is the investigation of the rotational spectrum of one of the simplest dinitriles N≡C-CH2-CH2-C≡N, succinonitrile, whose actual rotational parameters are not precise enough to allow its detection in the ISM. In addition, the rotational spectra for its vibrational exicted states will be analyzed. METHODS The rotational spectra of succinonitrile was measured in the frequency range 72-116.5 GHz using a new broadband millimeter-wave spectrometer based on radio astronomy receivers with Fast Fourier Transform backends. The identification of the vibrational excited states of succinonitrile was supported by high-level ab initio calculations on the harmonic and anharmonic force fields. RESULTS A total of 459 rotational transitions with maximum values of J and Ka quantum numbers 70 and 14, respectively, were measured for the ground vibrational state of succinonitrile. The analysis allowed us to accurately determine the rotational, quartic and sextic centrifugal distortion constants. Up to eleven vibrational excited states, resulting from the four lowest frequency vibrational modes ν 13, ν 12, ν 24 and ν 23 were identified. In addition to the four fundamental modes, we observed overtones together with some combination states. The rotational parameters for the ground state were employed to unsuccessfully search for succinonitrile in the cold and warm molecular clouds Orion KL, Sgr B2(N), B1-b and TMC-1, using the spectral surveys captured by IRAM 30m at 3mm and the Yebes 40m at 1.3cm and 7mm. CONCLUSIONS
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Affiliation(s)
- C. Cabezas
- Instituto de Física Fundamental (IFF-CSIC). Group of Molecular Astrophysics, C/ Serrano 123, 28006 Madrid, Spain
| | - C. Bermúdez
- Instituto de Física Fundamental (IFF-CSIC). Group of Molecular Astrophysics, C/ Serrano 123, 28006 Madrid, Spain
| | - J. D. Gallego
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - B. Tercero
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
- Observatorio Astronómico Nacional (OAN-IGN), C/ Alfonso XII 3, 28014 Madrid, Spain
| | - J. M. Hernández
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - I. Tanarro
- Instituto de Estructura de la Materia (IEM-CSIC). Molecular Physics Department. C/Serrano 123, 28006 Madrid, Spain
| | - V. J. Herrero
- Instituto de Estructura de la Materia (IEM-CSIC). Molecular Physics Department. C/Serrano 123, 28006 Madrid, Spain
| | - J. L. Doménech
- Instituto de Estructura de la Materia (IEM-CSIC). Molecular Physics Department. C/Serrano 123, 28006 Madrid, Spain
| | - J. Cernicharo
- Instituto de Física Fundamental (IFF-CSIC). Group of Molecular Astrophysics, C/ Serrano 123, 28006 Madrid, Spain
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Cernicharo J, Velilla-Prieto L, Agúndez M, Pardo J, Fonfría J, Quintana-Lacaci G, Cabezas C, Bermúdez C, Guélin M. Discovery of the first Ca-bearing molecule in space: CaNC. Astron Astrophys 2019; 627:L4. [PMID: 31327871 PMCID: PMC6640036 DOI: 10.1051/0004-6361/201936040] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report on the detection of calcium isocyanide, CaNC, in the carbon-rich evolved star IRC+10216. We derived a column density for this species of (2±0.5)×1011 cm-2. Based on the observed line profiles and the modelling of its emission through the envelope, the molecule has to be produced in the intermediate and outer layers of the circumstellar envelope where other metal-isocyanides have previously been found in this source. The abundance ratio of CaNC relative to MgNC and FeCN is ≃1/60 and ≃1, respectively. We searched for the species CaF, CaCl, CaC, CaCCH, and CaCH3 for which accurate frequency predictions are available. Only upper limits have been obtained for these molecules.
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Affiliation(s)
- J. Cernicharo
- Grupo de Astrofísica Molecular. Instituto de Física Fundamental (IFF-CSIC). C/Serrano 121, 28006 Madrid, Spain
| | - L. Velilla-Prieto
- Grupo de Astrofísica Molecular. Instituto de Física Fundamental (IFF-CSIC). C/Serrano 121, 28006 Madrid, Spain
- Department of Space, Earth and Environment, Chalmers University of Technology, Onsala Space Observatory, 439 92 Onsala, Sweden
| | - M. Agúndez
- Grupo de Astrofísica Molecular. Instituto de Física Fundamental (IFF-CSIC). C/Serrano 121, 28006 Madrid, Spain
| | - J.R. Pardo
- Grupo de Astrofísica Molecular. Instituto de Física Fundamental (IFF-CSIC). C/Serrano 121, 28006 Madrid, Spain
| | - J.P. Fonfría
- Grupo de Astrofísica Molecular. Instituto de Física Fundamental (IFF-CSIC). C/Serrano 121, 28006 Madrid, Spain
| | - G. Quintana-Lacaci
- Grupo de Astrofísica Molecular. Instituto de Física Fundamental (IFF-CSIC). C/Serrano 121, 28006 Madrid, Spain
| | - C. Cabezas
- Grupo de Astrofísica Molecular. Instituto de Física Fundamental (IFF-CSIC). C/Serrano 121, 28006 Madrid, Spain
| | - C. Bermúdez
- Grupo de Astrofísica Molecular. Instituto de Física Fundamental (IFF-CSIC). C/Serrano 121, 28006 Madrid, Spain
| | - M. Guélin
- Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, F-38406, Saint Martin d’Hères, France
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Agúndez M, Marcelino N, Cernicharo J, Roueff E, Tafalla M. A sensitive λ 3 mm line survey of L483: A broad view of the chemical composition of a core around a Class 0 object. Astron Astrophys 2019; 625:A147. [PMID: 31327870 PMCID: PMC6640051 DOI: 10.1051/0004-6361/201935164] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
An exhaustive chemical characterization of dense cores is mandatory to our understanding of chemical composition changes from a starless to a protostellar stage. However, only a few sources have had their molecular composition characterized in detail. Here we present a λ 3 mm line survey of L483, a dense core around a Class 0 protostar, which was observed with the IRAM 30m telescope in the 80-116 GHz frequency range. We detected 71 molecules (140 including different isotopologs), most of which are present in the cold and quiescent ambient cloud according to their narrow lines (FWHM ~0.5 km s-1) and low rotational temperatures (≲10 K). Of particular interest among the detected molecules are the cis isomer of HCOOH, the complex organic molecules HCOOCH3, CH3OCH3, and C2H5OH, a wide variety of carbon chains, nitrogen oxides like N2O, and saturated molecules like CH3SH, in addition to eight new interstellar molecules (HCCO, HCS, HSC, NCCNH+, CNCN, NCO, H2NCO+, and NS+) whose detection has already been reported. In general, fractional molecular abundances in L483 are systematically lower than in TMC-1 (especially for carbon chains), tend to be higher than in L1544 and B1-b, and are similar to those in L1527. Apart from the overabundance of carbon chains in TMC-1, we find that L483 does not have a marked chemical differentiation with respect to starless/prestellar cores like TMC-1 and L1544, although it does chemically differentiate from Class 0 hot corino sources like IRAS 16293-2422. This fact suggests that the chemical composition of the ambient cloud of some Class 0 sources could be largely inherited from the dark cloud starless/prestellar phase. We explore the use of potential chemical evolutionary indicators, such as the HNCO/C3S, SO2/C2S, and CH3SH/C2S ratios, to trace the prestellar/protostellar transition. We also derived isotopic ratios for a variety of molecules, many of which show isotopic ratios close to the values for the local interstellar medium (remarkably all those involving 34S and 33S), while there are also several isotopic anomalies like an extreme depletion in 13C for one of the two isotopologs of c-C3H2, a drastic enrichment in 18O for SO and HNCO (SO being also largely enriched in 17O), and different abundances for the two 13C substituted species of C2H and the two 15N substituted species of N2H+. We report the first detection in space of some minor isotopologs like c-C3D. The exhaustive chemical characterization of L483 presented here, together with similar studies of other prestellar and protostellar sources, should allow us to identify the main factors that regulate the chemical composition of cores along the process of formation of low-mass protostars.
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Affiliation(s)
- M Agúndez
- Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006 Madrid, Spain
| | - N Marcelino
- Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006 Madrid, Spain
| | - J Cernicharo
- Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006 Madrid, Spain
| | - E Roueff
- Sorbonne Université, Observatoire de Paris, Université PSL, CNRS, LERMA, F-92190 Meudon, France
| | - M Tafalla
- Observatorio Astronómico Nacional, C/ Alfonso XII 3, E-28014 Madrid, Spain
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Cernicharo J, Gallego JD, López-Pérez JA, Tercero F, Tanarro I, Beltrán F, de Vicente P, Lauwaet K, Alemán B, Moreno E, Herrero VJ, Doménech JL, Ramírez SI, Bermúdez C, Peláez RJ, Patino-Esteban M, López-Fernández I, García-Álvaro S, García-Carreño P, Cabezas C, Malo I, Amils R, Sobrado J, Diez-González C, Hernandéz J, Tercero B, Santoro G, Martínez L, Castellanos M, Vaquero Jiménez B, Pardo JR, Barbas L, López-Fernández J, Aja B, Leuther A, Martín-Gago JA. Broad band high resolution rotational spectroscopy for Laboratory Astrophysics. Astron Astrophys 2019; 626:10.1051/0004-6361/201935197. [PMID: 31186577 PMCID: PMC6557716 DOI: 10.1051/0004-6361/201935197] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We present a new experimental setup devoted to the study of gas phase molecules and processes using broad band high spectral resolution rotational spectroscopy. A reactor chamber has been equipped with radio receivers similar to those used by radio astronomers to search for molecular emission in space. The whole Q (31.5-50 GHz) and W bands (72-116.5 GHz) are available for rotational spectroscopy observations. The receivers are equipped with 16×2.5 GHz Fast Fourier Transform spectrometers with a spectral resolution of 38.14 kHz allowing the simultaneous observation of the complete Q band and one third of the W band. The whole W band can be observed in three settings in which the Q band is always observed. Species such as CH3CN, OCS, and SO2 are detected, together with many of their isotopologues and vibrationally excited states, in very short observing times. The system permits automatic overnight observations and integration times as long as 2.4×105 seconds have been reached. The chamber is equipped with a radiofrequency source to produce cold plasmas and with four ultraviolet lamps to study photochemical processes. Plasmas of CH4, N2, CH3CN, NH3, O2, and H2, among other species, have been generated and the molecular products easily identified by their rotational spectrum, and mass spectrometry and optical spectroscopy. Finally, the rotational spectrum of the lowest energy conformer of CH3CH2NHCHO (N-Ethylformamide), a molecule previously characterized in microwave rotational spectroscopy, has been measured up to 116.5 GHz allowing the accurate determination of its rotational and distortion constants and its search in space.
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Affiliation(s)
- J. Cernicharo
- Instituto de Física Fundamental (IFF. CSIC). Group of Molecular Astrophysics, C/Serrano 123, 28006 Madrid, Spain
| | - J. D. Gallego
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J. A. López-Pérez
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - F. Tercero
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - I. Tanarro
- Instituto de Estructura de la Materia (IEM. CSIC). Molecular Physics Department. C/Serrano 123, 28006 Madrid, Spain
| | - F. Beltrán
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - P. de Vicente
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - K. Lauwaet
- Instituto de Ciencia de Materiales de Madrid (ICMM. CSIC). Materials Science Factory. Structure of Nanoscopic Systems Group, ESISNA. C/Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
- IMDEA Nanociencia, Ciudad Universitaria de Cantoblanco, 28049 Cantoblanco, Madrid, Spain
| | - B. Alemán
- Instituto de Ciencia de Materiales de Madrid (ICMM. CSIC). Materials Science Factory. Structure of Nanoscopic Systems Group, ESISNA. C/Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
- IMDEA Materiales, C/Eric Kandel 2, Tecnogetafe, 28906 Getafe, Madrid, Spain
| | - E. Moreno
- Instituto de Física Fundamental (IFF. CSIC). Group of Molecular Astrophysics, C/Serrano 123, 28006 Madrid, Spain
| | - V. J. Herrero
- Instituto de Estructura de la Materia (IEM. CSIC). Molecular Physics Department. C/Serrano 123, 28006 Madrid, Spain
| | - J. L. Doménech
- Instituto de Estructura de la Materia (IEM. CSIC). Molecular Physics Department. C/Serrano 123, 28006 Madrid, Spain
| | - S. I. Ramírez
- Instituto de Física Fundamental (IFF. CSIC). Group of Molecular Astrophysics, C/Serrano 123, 28006 Madrid, Spain
- Centro de Investigaciones Químicas, UAEM. Av. Universidad, 1001 Col. Chamilpa 62209, Cuernavaca, Morelos Mexico
| | - C. Bermúdez
- Instituto de Física Fundamental (IFF. CSIC). Group of Molecular Astrophysics, C/Serrano 123, 28006 Madrid, Spain
| | - R. J. Peláez
- Instituto de Estructura de la Materia (IEM. CSIC). Molecular Physics Department. C/Serrano 123, 28006 Madrid, Spain
| | - M. Patino-Esteban
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - I. López-Fernández
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - S. García-Álvaro
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - P. García-Carreño
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - C. Cabezas
- Instituto de Física Fundamental (IFF. CSIC). Group of Molecular Astrophysics, C/Serrano 123, 28006 Madrid, Spain
| | - I. Malo
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - R. Amils
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J. Sobrado
- Centro de Astrobiología (CSIC-INTA), Crta. de Torrejón de Ardoz a Ajalvir, km 4. Torrejón de Ardoz, 28850, Spain
| | - C. Diez-González
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J.M. Hernandéz
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - B. Tercero
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - G. Santoro
- Instituto de Ciencia de Materiales de Madrid (ICMM. CSIC). Materials Science Factory. Structure of Nanoscopic Systems Group, ESISNA. C/Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
| | - L. Martínez
- Instituto de Ciencia de Materiales de Madrid (ICMM. CSIC). Materials Science Factory. Structure of Nanoscopic Systems Group, ESISNA. C/Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
| | - M. Castellanos
- Instituto de Física Fundamental (IFF. CSIC). Group of Molecular Astrophysics, C/Serrano 123, 28006 Madrid, Spain
| | - B. Vaquero Jiménez
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J. R. Pardo
- Instituto de Física Fundamental (IFF. CSIC). Group of Molecular Astrophysics, C/Serrano 123, 28006 Madrid, Spain
| | - L. Barbas
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J.A. López-Fernández
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - B. Aja
- Universidad de Cantabria, Department of Communication Engineering, Avda. Los Castros, 39005 Santander, Spain
| | - A. Leuther
- Fraunhofer Institut fur Angewandte Festkorperphysik, Tullastresse 72, 79108 Freiburg, Germany
| | - J. A. Martín-Gago
- Instituto de Ciencia de Materiales de Madrid (ICMM. CSIC). Materials Science Factory. Structure of Nanoscopic Systems Group, ESISNA. C/Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
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Gall AC, Foster AR, Silwal R, Dreiling JM, Borovik A, Kilgore E, Ajello M, Gillaspy JD, Ralchenko Y, Takács E. EBIT Observation of Ar Dielectronic Recombination Lines near the Unknown Faint X-Ray Feature Found in the Stacked Spectrum of Galaxy Clusters. Astrophys J 2019; 872:10.3847/1538-4357/ab0177. [PMID: 34795454 PMCID: PMC8596318 DOI: 10.3847/1538-4357/ab0177] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Motivated by possible atomic origins of the unidentified emission line detected at 3.55-3.57 keV in a stacked spectrum of galaxy clusters, an electron beam ion trap (EBIT) was used to investigate the resonant dielectronic recombination (DR) process in highly charged argon ions as a possible contributor to the emission feature. The He-like Ar DR-induced transition 1s22l-1s2l3l' was suggested to produce a 3.62 keV photon near the unidentified line at 3.57 keV and was the starting point of our investigation. The collisional-radiative model NOMAD was used to create synthetic spectra for comparison with both our EBIT measurements and with spectra produced with the AtomDB database/Astrophysical Plasma Emission Code (APEC) used in the Bulbul et al. work. Excellent agreement was found between the NOMAD and EBIT spectra, providing a high level of confidence in the atomic data used. Comparison of the NOMAD and APEC spectra revealed a number of missing features in the AtomDB database near the unidentified line. At an electron temperature of T e = 1.72 keV, the inclusion of the missing lines in AtomDB increases the total flux in the 3.5-3.66 keV energy band by a factor of 2. While important, this extra emission is not enough to explain the unidentified line found in the galaxy cluster spectra.
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Affiliation(s)
- Amy C Gall
- Clemson University, Department of Physics and Astronomy, Clemson, SC 29634-0978, USA
| | - Adam R Foster
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
| | - Roshani Silwal
- Clemson University, Department of Physics and Astronomy, Clemson, SC 29634-0978, USA
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Joan M Dreiling
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Alexander Borovik
- I. Physikalisches Institut, Justus-Liebig-Universität Gießen, D-35392 Giessen, Germany
| | - Ethan Kilgore
- Clemson University, Department of Physics and Astronomy, Clemson, SC 29634-0978, USA
| | - Marco Ajello
- Clemson University, Department of Physics and Astronomy, Clemson, SC 29634-0978, USA
| | - John D Gillaspy
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
- National Science Foundation, Alexandria, VA 22314, USA
| | - Yuri Ralchenko
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Endre Takács
- Clemson University, Department of Physics and Astronomy, Clemson, SC 29634-0978, USA
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
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Bermúdez C, Tercero B, Motiyenko RA, Margulès L, Cernicharo J, Ellinger Y, Guillemin JC. The millimeter-wave spectrum of methyl ketene and the astronomical search for it. Astron Astrophys 2018; 619:A92. [PMID: 30595605 PMCID: PMC6309256 DOI: 10.1051/0004-6361/201833267] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
CONTEXT The analysis of isomeric species of a compound observed in the interstellar medium (ISM) is a useful tool to understand the chemistry of complex organic molecules. It could, likewise, assist in the detection of new species. AIMS Our goal consists in analyzing one of the two most stable species of the C3H4O family, methyl ketene, whose actual rotational parameters are not precise enough to allow its detection in the ISM. The obtained parameters will be used to search for it in the high-mass star-forming regions Orion KL and Sagittarius B2, as well as in the cold dark clouds TMC-1 in the Taurus Molecular Cloud and Barnard 1 (B1-b). METHODS A millimeter-wave room-temperature rotational spectrum of methyl ketene was recorded from 50 to 330 GHz. The internal rotation analysis of its ground state and first torsional excited state was performed with the rho-axis method employing the RAM36 program. RESULTS More than 3000 transitions of the rotational spectrum of the ground state (Kamax = 18) and first torsional excited state (Kamax = 13) of methyl ketene were fitted using a Hamiltonian that contains 41 parameters with an RMS (root mean square) of 41 kHz. Column density limits were calculated but no lines were detected in the ISM belonging to methyl ketene.
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Affiliation(s)
- C Bermúdez
- Université de Lille, Faculté des Sciences et Technologies, Département Physique, Laboratoire de Physique des Lasers, Atomes et Molécules, UMR CNRS 8523, 59655 Villeneuve d'Ascq Cedex, France
| | - B Tercero
- Observatorio Astronómico Nacional (IGN), C/Alfonso XII 3, 28014 Madrid, Spain
| | - R A Motiyenko
- Université de Lille, Faculté des Sciences et Technologies, Département Physique, Laboratoire de Physique des Lasers, Atomes et Molécules, UMR CNRS 8523, 59655 Villeneuve d'Ascq Cedex, France
| | - L Margulès
- Université de Lille, Faculté des Sciences et Technologies, Département Physique, Laboratoire de Physique des Lasers, Atomes et Molécules, UMR CNRS 8523, 59655 Villeneuve d'Ascq Cedex, France
| | - J Cernicharo
- Instituto de Física Fundamental, Dpt. of Molecular Astrophysics, CSIC, C/ Serrano 121, 28006, Madrid, Spain
| | - Y Ellinger
- Sorbone Université, CNRS, Laboratoire de Chimie Théorique, LCT, F. 75005 Paris, France
| | - J-C Guillemin
- Univ. Rennes, Ecole Nationale Supérieure de Chimie de Rennes, CNRS, ISCR - UMR6226, F-35000 Rennes, France
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Kolesniková L, Peña I, Alonso ER, Tercero B, Cernicharo J, Mata S, Alonso JL. Laboratory rotational spectrum and astronomical search for methoxyacetaldehyde. Astron Astrophys 2018; 619:A67. [PMID: 30555173 PMCID: PMC6290985 DOI: 10.1051/0004-6361/201833773] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
CONTEXT Methoxyacetaldehyde belongs to a group of structural isomers with the general formula C3H6O2, of which methyl acetate and ethyl formate are known interstellar molecules. Rotational data available for methoxyacetaldehyde are limited to 40 GHz, which makes predictions at higher frequencies rather uncertain. AIMS The aim of this work is to provide accurate experimental frequencies of methoxyacetaldehyde in the millimeter-wave region to support its detection in the interstellar medium. METHODS The rotational spectrum of methoxyacetaldehyde was recorded at room-temperature from 75 to 120 GHz and from 170 to 310 GHz using the millimeter-wave spectrometer in Valladolid. Additional measurements were also performed at conditions of supersonic expansion from 6 to 18 GHz. The assigned rotational transitions were analyzed using the S -reduced semirigid-rotor Hamiltonian. RESULTS We newly assigned over 1000 lines for the most stable conformer of methoxyacetaldehyde in its ground state and five lowest excited vibrational states, and precise sets of spectroscopic constants were obtained. We searched for spectral features of methoxyacetaldehyde in the high-mass star-forming regions Orion KL and Sagittarius B2, as well as in the cold dark cloud Barnard 1 (B1-b). No lines belonging to methoxyacetaldehyde were detected above the detection limit of our data. We provide upper limits to the methoxyacetaldehyde colum density in these sources.
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Affiliation(s)
- L Kolesniková
- Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, 47011 Valladolid, Spain
| | - I Peña
- Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, 47011 Valladolid, Spain
| | - E R Alonso
- Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, 47011 Valladolid, Spain
| | - B Tercero
- Observatorio Astronómico Nacional (OAN-IGN), Calle Alfonso XII 3, 28014 Madrid, Spain
| | - J Cernicharo
- Instituto de Física Fundamental (IFF-CSIC), Calle Serrano 123, 28006 Madrid, Spain
| | - S Mata
- Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, 47011 Valladolid, Spain
| | - J L Alonso
- Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, 47011 Valladolid, Spain
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Santana JA, Lopez-Dauphin NA, Morales Butler EJ, Beiersdorfer P. RELATIVISTIC MR-MP ENERGY LEVELS FOR L-SHELL IONS OF SULFUR AND ARGON. Astrophys J Suppl Ser 2018; 238:34. [PMID: 30369650 PMCID: PMC6200352 DOI: 10.3847/1538-4365/aae14e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Calculated level energies for valence and K-vacancy states are provided for the ion series S VII - S XIV and Ar IX - Ar XVI. The calculations were performed with the relativistic Multi-Reference Mxller-Plesset Perturbation Theory method (MR-MP). The data set includes all the level energies with configurations 1s 22(s, p) q , 1s 22(s, p) q-1 nl, 1s 12(s, p) q+1, 1s 12(s, p) q nl, 2(s, p) q+2 and 2(s, p) q+1 nl, where 1 ≤ q ≤ 8, n ≤ 5 and l ≤ 3. We have compared our results with data from the National Institute of Standards and Technology (NIST) on-line database and with previous calculations. The average deviation of valence level energies ranges from 0.16 eV in Ne-like ions to 0.01 eV in Li-like ions, showing that the present MR-MP valence level energies are highly accurate. In the case of K-vacancy states, the deviation is generally below 0.3 eV for Li-like S XIV and Ar XVI. The deviation for K-vacancy energies in other L-shell ions (Be-, B-, C-, N- and O-like Ar ions) is higher but likely because the NIST-recommended values have a higher uncertainty. The data set includes many n = 4 and n = 5 valence and K-vacancy levels in L-shell ions of S and Ar not previously reported. The data can be used for line identification and modeling of L-shell ions of S and Ar in astrophysical and laboratory-generated plasmas, and as energy references in the absence of more accurate laboratory measurements.
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Affiliation(s)
- Juan A. Santana
- Department of Chemistry, The University of Puerto Rico at Cayey, P. O. Box 372230, Cayey, PR 00737-2230, USA
| | - Nahyr A. Lopez-Dauphin
- Department of Chemistry, The University of Puerto Rico at Cayey, P. O. Box 372230, Cayey, PR 00737-2230, USA
- Department of Chemistry, 359 Natural Sciences Complex, University at Bu alo, Bu alo, NY 14260-3000, USA
| | - Emmanuel J. Morales Butler
- Department of Natural Sciences - Mathematics, The University of Puerto Rico at Utuado, P.O. Box 2500 Utuado, PR 00641, USA
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Cernicharo J, Guélin M, Agúndez M, Pardo JR, Massalkhi S, Fonfría JP, Velilla Prieto L, Quintana-Lacaci G, Marcelino N, Marka C, Navarro S, Kramer C. IRC +10216 as a spectroscopic laboratory: improved rotational constants for SiC 2, its isotopologues, and Si 2C. Astron Astrophys 2018; 618:A4. [PMID: 30429616 PMCID: PMC6231541 DOI: 10.1051/0004-6361/201833335] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
This work presents a detailed analysis of the laboratory and astrophysical spectral data available for 28SiC2, 29SiC2,30SiC2, Si13CC, and Si2C. New data on the rotational lines of these species between 70 and 350 GHz have been obtained with high spectral resolution (195 kHz) with the IRAM 30m telescope in the direction of the circumstellar envelope IRC +10216. Frequency measurements can reach an accuracy of 50 kHz for features observed with a good signal to noise ratio. From the observed astrophysical lines and the available laboratory data new rotational and centrifugal distortion constants have been derived for all the isotopologues of SiC2, allowing to predict their spectrum with high accuracy in the millimeter and submillimeter domains. Improved rotational and centrifugal distortion constants have also been obtained for disilicon carbide, Si2C. This work shows that observations of IRC +10216 taken with the IRAM 30m telescope, with a spectral resolution of 195 kHz, can be used for any molecular species detected in this source to derive, or improve, its rotational constants. Hence, IRC +10216 in addition to be one the richest sources in molecular species in the sky, can also be used as a state-of-the-art spectroscopy laboratory in the millimeter and submillimeter domains.
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Affiliation(s)
- J. Cernicharo
- Group of Molecular Astrophysics, Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006, Madrid, Spain
| | - M. Guélin
- Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, F-38406, Saint Martin d'Hères, France
| | - M. Agúndez
- Group of Molecular Astrophysics, Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006, Madrid, Spain
| | - J. R. Pardo
- Group of Molecular Astrophysics, Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006, Madrid, Spain
| | - S. Massalkhi
- Group of Molecular Astrophysics, Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006, Madrid, Spain
| | - J. P. Fonfría
- Group of Molecular Astrophysics, Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006, Madrid, Spain
| | - L. Velilla Prieto
- Group of Molecular Astrophysics, Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006, Madrid, Spain
| | - G. Quintana-Lacaci
- Group of Molecular Astrophysics, Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006, Madrid, Spain
| | - N. Marcelino
- Group of Molecular Astrophysics, Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006, Madrid, Spain
| | - C. Marka
- Instituto de Radioastronomía Milimétrica, Avenida Divina Pastora 7, E-18012, Granada, Spain
| | - S. Navarro
- Instituto de Radioastronomía Milimétrica, Avenida Divina Pastora 7, E-18012, Granada, Spain
| | - C. Kramer
- Instituto de Radioastronomía Milimétrica, Avenida Divina Pastora 7, E-18012, Granada, Spain
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Kolesniková L, Alonso ER, Tercero B, Cernicharo J, Alonso JL. Millimeter wave spectra of ethyl isocyanate and searches for it in Orion KL and Sgr B2. Astron Astrophys 2018; 616:A173. [PMID: 30369619 PMCID: PMC6203308 DOI: 10.1051/0004-6361/201833223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
CONTEXT Relatively high abundances of methyl isocyanate (CH3NCO), a methyl derivative of isocyanic acid (HNCO), found in the Orion KL and Sgr B2 molecular clouds suggest that its ethyl derivative, ethyl isocyanate (CH3CH2NCO), may also be present. AIMS The aim of this work is to provide accurate experimental frequencies of ethyl isocyanate in its ground and excited vibrational states in the millimeter wave region to support searches for it in the interstellar medium. METHODS The rotational spectrum of ethyl isocyanate was recorded at room temperature from 80 to 340 GHz using the millimeter wave spectrometer in Valladolid. Assigned rotational transitions were analyzed using the S -reduced semirigid-rotor Hamiltonian. RESULTS More than 1100 distinct frequency lines were analyzed for the ground vibrational state of the cis conformer as well as for three vibrational satellites corresponding to successive excitation of the lowest-energy C-N torsional mode. Newly determined rotational and centrifugal distortion constants were used for searches of spectral features of ethyl isocyanate in Orion KL and Sgr B2 clouds. Upper limits to CH3CH2NCO in these high-mass star-forming regions were obtained.
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Affiliation(s)
- L Kolesniková
- Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, E-47011 Valladolid, Spain
| | - E R Alonso
- Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, E-47011 Valladolid, Spain
| | - B Tercero
- Observatorio Astronómico Nacional (OAN-IGN). Calle Alfonso XII, 3, E-28014 Madrid, Spain
| | - J Cernicharo
- Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3,E-28049 Cantoblanco, Spain
| | - J L Alonso
- Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, E-47011 Valladolid, Spain
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Agúndez M, Marcelino N, Cernicharo J. Discovery of Interstellar Isocyanogen (CNCN): Further Evidence that Dicyanopolyynes are Abundant in Space. Astrophys J Lett 2018; 861:L22. [PMID: 30186588 PMCID: PMC6120679 DOI: 10.3847/2041-8213/aad089] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
It is thought that dicyanopolyynes could be potentially abundant interstellar molecules, although their lack of dipole moment makes it impossible to detect them through radioastronomical techniques. Recently, the simplest member of this chemical family, cyanogen (NCCN), was indirectly probed for the first time in interstellar space through the detection of its protonated form toward the dense clouds L483 and TMC-1. Here we present a second firm evidence of the presence of NCCN in interstellar space, namely the detection of the metastable and polar isomer isocyanogen (CNCN). This species has been identified in L483 and tentatively in TMC-1 by observing various rotational transitions in the λ 3 mm band with the IRAM 30m telescope. We derive beam-averaged column densities for CNCN of 1.6 × 1012 cm-2 in L483 and 9 × 1011 cm-2 in TMC-1, which imply fractional abundances relative to H2 in the range (5 - 9) × 10-11. While the presence of NCCN in interstellar clouds seems out of doubt owing to the detection of NCCNH+ and CNCN, putting tight constraints on its abundance is still hampered by the poor knowledge of the chemistry that links NCCN with NCCNH+ and especially with CNCN. We estimate that NCCN could be fairly abundant, in the range 10-9-10-7 relative to H2, as other abundant nitriles like HCN and HC3N.
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Affiliation(s)
- M Agúndez
- Instituto de Física Fundamental, CSIC, C/ Serrano 123, 28006 Madrid, Spain
| | - N Marcelino
- Instituto de Física Fundamental, CSIC, C/ Serrano 123, 28006 Madrid, Spain
| | - J Cernicharo
- Instituto de Física Fundamental, CSIC, C/ Serrano 123, 28006 Madrid, Spain
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Abstract
Level energies are reported for Si V, Si VI, Si VII, Si VIII, Si IX, Si X, Si XI and Si XII. The energies have been calculated with the relativistic Multi-Reference Møller-Plesset Perturbation Theory method and include valence and K-vacancy states with nl up to 5f. The accuracy of the calculated level energies is established by comparison with the recommended data listed in the National Institute of Standards and Technology (NIST) on-line database. The average deviation of valence level energies ranges from 0.20 eV in Si V to 0.04 eV in Si XII. For K-vacancy states, the available values recommended in the NIST database are limited to Si XII and Si XIII. The average energy deviation is below 0.3 eV for K-vacancy states. The extensive and accurate dataset presented here greatly augments the amount of available reference level energies. We expect our data to ease the line identification of L-shell ions of Si in celestial sources and laboratory generated plasmas, and to serve as energy references in the absence of more accurate laboratory measurements.
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Agúndez M, Marcelino N, Cernicharo J, Tafalla M. Detection of interstellar HCS and its metastable isomer HSC: new pieces in the puzzle of sulfur chemistry. Astron Astrophys 2018; 611:L1. [PMID: 29983448 PMCID: PMC6031296 DOI: 10.1051/0004-6361/201832743] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We present the first identification in interstellar space of the thioformyl radical (HCS) and its metastable isomer HSC. These species were detected toward the molecular cloud L483 thanks to observations carried out with the IRAM 30m telescope in the λ 3 mm band. We derive beam-averaged column densities of 7 × 1012 cm-2 for HCS and 1.8 × 1011 cm-2 for HSC, which translate to fractional abundances relative to H2 of 2 × 10-10 and 6 × 10-12, respectively. Although the amount of sulfur locked by these radicals is low, their detection allows to put interesting constraints on the chemistry of sulfur in dark clouds. Interestingly, the H2CS/HCS abundance ratio is found to be quite low, ~ 1, in contrast with the oxygen analogue case, in which the H2CO/HCO abundance ratio is around 10 in dark clouds. Moreover, the radical HCS is found to be more abundant than its oxygen analogue, HCO. The metastable species HOC, the oxygen analogue of HSC, has not been yet observed in space. These observational constraints are confronted with the outcome of a recent model of the chemistry of sulfur in dark clouds. The model underestimates the fractional abundance of HCS by at least one order of magnitude, overestimates the H2CS/HCS abundance ratio, and does not provide an abundance prediction for the metastable isomer HSC. These observations should prompt a revision of the chemistry of sulfur in interstellar clouds.
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Affiliation(s)
- M Agúndez
- Instituto de Física Fundamental, CSIC, C/ Serrano 123, 28006 Madrid, Spain
| | - N Marcelino
- Instituto de Física Fundamental, CSIC, C/ Serrano 123, 28006 Madrid, Spain
| | - J Cernicharo
- Instituto de Física Fundamental, CSIC, C/ Serrano 123, 28006 Madrid, Spain
| | - M Tafalla
- Observatorio Astronómico Nacional (OAN), C/ Alfonso XII 3, 28014 Madrid, Spain
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Cernicharo J, Lefloch B, Agúndez M, Bailleux S, Margulès L, Roueff E, Bachiller R, Marcelino N, Tercero B, Vastel C, Caux E. Discovery of the Ubiquitous Cation NS + in Space Confirmed by Laboratory Spectroscopy. Astrophys J Lett 2018; 853:L22. [PMID: 29983906 PMCID: PMC6031291 DOI: 10.3847/2041-8213/aaa83a] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We report the detection in space of a new molecular species which has been characterized spectroscopically and fully identified from astrophysical data. The observations were carried out with the 30m IRAM telescopea. The molecule is ubiquitous as its J=2→1 transition has been found in cold molecular clouds, prestellar cores, and shocks. However, it is not found in the hot cores of Orion-KL and in the carbon-rich evolved star IRC+10216. Three rotational transitions in perfect harmonic relation J' = 2/3/5 have been identified in the prestellar core B1b. The molecule has a 1Σ electronic ground state and its J=2→1 transition presents the hyperfine structure characteristic of a molecule containing a nucleus with spin 1. A careful analysis of possible carriers shows that the best candidate is NS+. The derived rotational constant agrees within 0.3-0.7% with ab initio calculations. NS+ was also produced in the laboratory to unambiguously validate the astrophysical assignment. The observed rotational frequencies and determined molecular constants confirm the discovery of the nitrogen sulfide cation in space. The chemistry of NS+ and related nitrogen-bearing species has been analyzed by means of a time-dependent gas phase model. The model reproduces well the observed NS/NS+ abundance ratio, in the range 30-50, and indicates that NS+ is formed by reactions of the neutral atoms N and S with the cations SH+ and NH+, respectively.
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Affiliation(s)
- J Cernicharo
- Group of Molecular Astrophysics. ICMM. CSIC. C/Sor Juana Inés de La Cruz 3, E-28049, Madrid, Spain
- Dpt. of Molecular Astrophysics. IFF. CSIC. C/Serrano 123, E-28006, Madrid, Spain
| | - B Lefloch
- Université Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
| | - M Agúndez
- Group of Molecular Astrophysics. ICMM. CSIC. C/Sor Juana Inés de La Cruz 3, E-28049, Madrid, Spain
- Dpt. of Molecular Astrophysics. IFF. CSIC. C/Serrano 123, E-28006, Madrid, Spain
| | - S Bailleux
- Laboratoire de Physique des Lasers, Atomes et Molécules, UMR 8523 CNRS, Université Lille, 59655 Villeneuve d'Ascq Cedex, France
| | - L Margulès
- Laboratoire de Physique des Lasers, Atomes et Molécules, UMR 8523 CNRS, Université Lille, 59655 Villeneuve d'Ascq Cedex, France
| | - E Roueff
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universits, UPMC Univ. Paris 06, F-92190 Meudon, France
| | - R Bachiller
- Observatorio Astronómico Nacional (OAN, IGN), Calle Alfonso XII, 3, 28014 Madrid, Spain
| | - N Marcelino
- Group of Molecular Astrophysics. ICMM. CSIC. C/Sor Juana Inés de La Cruz 3, E-28049, Madrid, Spain
- Dpt. of Molecular Astrophysics. IFF. CSIC. C/Serrano 123, E-28006, Madrid, Spain
| | - B Tercero
- Group of Molecular Astrophysics. ICMM. CSIC. C/Sor Juana Inés de La Cruz 3, E-28049, Madrid, Spain
- Observatorio Astronómico Nacional (OAN, IGN), Calle Alfonso XII, 3, 28014 Madrid, Spain
| | - C Vastel
- IRAP, Université de Toulouse, CNRS, UPS, CNES, Toulouse, France
| | - E Caux
- IRAP, Université de Toulouse, CNRS, UPS, CNES, Toulouse, France
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Abstract
We present the detection of C4H2 for first time in the envelope of the C-rich AGB star IRC+10216 based on high spectral resolution mid-IR observations carried out with the Texas Echelon-cross-Echelle Spectrograph (TEXES) mounted on the Infrared Telescope Facility (IRTF). The obtained spectrum contains 24 narrow absorption features above the detection limit identified as lines of the ro-vibrational C4H2 band ν 6 + ν 8 ( σ u + ) . The analysis of these lines through a ro-vibrational diagram indicates that the column density of C4H2 is (2.4 ± 1.5) × 1016 cm-2. Diacetylene is distributed in two excitation populations accounting for 20 and 80% of the total column density and with rotational temperatures of 47 ± 7 and 420 ± 120 K, respectively. This two-folded rotational temperature suggests that the absorbing gas is located beyond ≃ 0 · " 4 ≃ 20 R ⋆ from the star with a noticeable cold contribution outwards from ≃ 10″ ≃ 500R⋆. This outer shell matches up with the place where cyanoacetylenes and carbon chains are known to form due to the action of the Galactic dissociating radiation field on the neutral gas coming from the inner layers of the envelope.
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Affiliation(s)
- J P Fonfría
- Molecular Astrophysics Group, Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049, Madrid (Spain)
| | - M Agúndez
- Molecular Astrophysics Group, Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049, Madrid (Spain)
| | - J Cernicharo
- Molecular Astrophysics Group, Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049, Madrid (Spain)
| | - M J Richter
- Physics Dept. - UC Davis, One Shields Ave., Davis, CA 95616 (USA)
- Visiting Astronomer at the Infrared Telescope Facility, which is operated by the University of Hawaii under contract NNH14CK55B from the National Aeronautics and Space Administration
| | - J H Lacy
- Astronomy Dept., University of Texas, Austin, TX 78712 (USA)
- Visiting Astronomer at the Infrared Telescope Facility, which is operated by the University of Hawaii under contract NNH14CK55B from the National Aeronautics and Space Administration
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Kolesniková L, Tercero B, Alonso ER, Guillemin JC, Cernicharo J, Alonso JL. Rotational spectrum of methoxyamine up to 480 GHz: a laboratory study and astronomical search. Astron Astrophys 2018; 609:A24. [PMID: 29983447 PMCID: PMC6031297 DOI: 10.1051/0004-6361/201730744] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
AIMS Methoxyamine is a potential interstellar amine that has been predicted by gas-grain chemical models for the formation of complex molecules. The aim of this work is to provide direct experimental frequencies of its ground-vibrational state in the millimeter- and submillimeter-wave regions to achieve its detection in the interstellar medium. METHODS Methoxyamine was chemically liberated from its hydrochloride salt, and its rotational spectrum was recorded at room temperature from 75 to 480 GHz using the millimeter-wave spectrometer in Valladolid. Many observed transitions revealed A-E splitting caused by the internal rotation of the methyl group, which had to be treated with specific internal rotation codes. RESULTS Over 400 lines were newly assigned for the most stable conformer of methoxyamine, and a precise set of spectroscopic constants was obtained. Spectral features of methoxyamine were then searched for in the Orion KL, Sgr B2, B1-b, and TMC-1 molecular clouds. Upper limits to the column density of methoxyamine were derived.
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Affiliation(s)
- L Kolesniková
- Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, 47011 Valladolid, Spain
| | - B Tercero
- Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Spain
| | - E R Alonso
- Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, 47011 Valladolid, Spain
| | - J-C Guillemin
- Institut des Sciences Chimiques de Rennes, École Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex 7, France
| | - J Cernicharo
- Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Spain
| | - J L Alonso
- Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, 47011 Valladolid, Spain
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Goicoechea JR, Cuadrado S, Pety J, Bron E, Black JH, Cernicharo J, Chapillon E, Fuente A, Gerin M. Spatially resolved images of reactive ions in the Orion Bar ,★★. Astron Astrophys 2017; 601:L9. [PMID: 28690335 PMCID: PMC5500010 DOI: 10.1051/0004-6361/201730716] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We report high angular resolution (4.9″×3.0″) images of reactive ions SH+, HOC+, and SO+ toward the Orion Bar photodissociation region (PDR). We used ALMA-ACA to map several rotational lines at 0.8 mm, complemented with multi-line observations obtained with the IRAM 30 m telescope. The SH+ and HOC+ emission is restricted to a narrow layer of 2″- to 10″-width (≈800 to 4000 AU depending on the assumed PDR geometry) that follows the vibrationally excited [Formula: see text] emission. Both ions efficiently form very close to the H/H2 transition zone, at a depth of Av≲1 mag into the neutral cloud, where abundant C+, S+, and [Formula: see text] coexist. SO+ peaks slightly deeper into the cloud. The observed ions have low rotational temperatures (Trot≈10-30 K≪Tk) and narrow line-widths (~2-3 km s-1), a factor of ≃2 narrower that those of the lighter reactive ion CH+. This is consistent with the higher reactivity and faster radiative pumping rates of CH+ compared to the heavier ions, which are driven relatively faster toward smaller velocity dispersion by elastic collisions and toward lower Trot by inelastic collisions. We estimate column densities and average physical conditions from an excitation model (n(H2)≈105-106 cm-3, n(e-)≈10 cm-3, and Tk≈200 K). Regardless of the excitation details, SH+ and HOC+ clearly trace the most exposed layers of the UV-irradiated molecular cloud surface, whereas SO+ arises from slightly more shielded layers.
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Affiliation(s)
| | - Sara Cuadrado
- Instituto de Ciencias de Materiales de Madrid (CSIC), 28049, Madrid, Spain
| | - Jérôme Pety
- Institut de Radioastronomie Millimétrique, 38406, Saint Martin d'Hères, France
- LERMA, Obs. de Paris, PSL Research University, CNRS, Sorbonne Universiteés, UPMC Univ. Paris 06, ENS, F-75005, France
| | - Emeric Bron
- Instituto de Ciencias de Materiales de Madrid (CSIC), 28049, Madrid, Spain
- LERMA, Obs. de Paris, PSL Research University, CNRS, Sorbonne Universiteés, UPMC Univ. Paris 06, ENS, F-75005, France
| | - John H Black
- Chalmers University of Technology, Onsala Space Observatory, 43992 Onsala, Sweden
| | - José Cernicharo
- Instituto de Ciencias de Materiales de Madrid (CSIC), 28049, Madrid, Spain
| | - Edwige Chapillon
- Institut de Radioastronomie Millimétrique, 38406, Saint Martin d'Hères, France
- OASU/LAB-UMR5804, CNRS, Universiteé Bordeaux, 33615 Pessac, France
| | - Asunción Fuente
- Observatorio Astronómico Nacional (IGN). Apartado 112, 28803 Alcalá de Henares, Spain
| | - Maryvonne Gerin
- LERMA, Obs. de Paris, PSL Research University, CNRS, Sorbonne Universiteés, UPMC Univ. Paris 06, ENS, F-75005, France
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Abstract
High spectral resolution mid-IR observations of ethylene (C2H4) towards the AGB star IRC+10216 were obtained using the Texas Echelon Cross Echelle Spectrograph (TEXES) at the NASA Infrared Telescope Facility (IRTF). Eighty ro-vibrational lines from the 10.5 µm vibrational mode ν7 with J ≲ 30 were detected in absorption. The observed lines are divided into two groups with rotational temperatures of 105 and 400 K (warm and hot lines). The warm lines peak at ≃ -14 km s-1 with respect to the systemic velocity, suggesting that they are mostly formed outwards from ≃ 20R⋆. The hot lines are centered at -10 km s-1 indicating that they come from a shell between 10 and 20R⋆. 35% of the observed lines are unblended and can be fitted with a code developed to model the emission of a spherically symmetric circumstellar envelope. The analysis of several scenarios reveal that the C2H4 abundance relative to H2 in the range 5 - 20R⋆ is 6.9 × 10-8 in average and it could be as high as 1.1 × 10-7. Beyond 20R⋆, it is 8.2 × 10-8. The total column density is (6.5 ± 3.0) × 1015 cm-2. C2H4 is found to be rotationally under local thermodynamical equilibrium (LTE) and vibrationally out of LTE. One of the scenarios that best reproduce the observations suggests that up to 25% of the C2H4 molecules at 20R⋆ could condense onto dust grains. This possible depletion would not influence significantly the gas acceleration although it could play a role in the surface chemistry on the dust grains.
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Affiliation(s)
- J P Fonfría
- Grupo de Astrofísica Molecular, Instituto de Ciencia de los Materiales, CSIC, C/ Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049, Madrid, Spain
| | - K H Hinkle
- National Optical Astronomy Observatory, P.O. Box 26732, Tucson, Arizona 85726, USA
| | - J Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Ciencia de los Materiales, CSIC, C/ Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049, Madrid, Spain
| | - M J Richter
- Physics Dept. - UC Davis, One Shields Ave., Davis, CA 95616 (USA)
| | - M Agúndez
- Grupo de Astrofísica Molecular, Instituto de Ciencia de los Materiales, CSIC, C/ Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049, Madrid, Spain
| | - L Wallace
- National Optical Astronomy Observatory, P.O. Box 26732, Tucson, Arizona 85726, USA
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Abstract
CONTEXT More than 30 cyanide derivatives of simple organic molecules have been detected in the interstellar medium, but only one dicarbonitrile has been found and that very recently. There is still a lack of high-resolution spectroscopic data particularly for dinitriles derivatives. The carbonyl cyanide molecule is a new and interesting candidate for astrophysical detection. It could be formed by the reaction of CO and CN radicals, or by substitution of the hydrogen atom by a cyano group in cyanoformaldehyde, HC(=O)CN, that has already been detected in the interstellar medium. AIMS The available data on the rotational spectrum of carbonyl cyanide is limited in terms of quantum number values and frequency range, and does not allow accurate extrapolation of the spectrum into the millimeter-wave range. To provide a firm basis for astrophysical detection of carbonyl cyanide we studied its millimeter-wave spectrum. METHODS The rotational spectrum of carbonyl cyanide was measured in the frequency range 152 - 308 GHz and analyzed using Watson's A- and S-reduction Hamiltonians. RESULTS The ground and first excited state of v5 vibrational mode were assigned and analyzed. More than 1100 distinct frequency lines of the ground state were fitted to produce an accurate set of rotational and centrifugal distortion constants up to the eighth order. The frequency predictions based on these constants should be accurate enough for astrophysical searches in the frequency range up to 500 GHz and for transition involving energy levels with J ≤ 100 and Ka ≤ 42. Based on the results we searched for interstellar carbonyl cyanide in available observational data without success. Thus, we derived upper limits to its column density in different sources.
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Affiliation(s)
- S B Bteich
- Laboratoire de Physique des Lasers, Atomes et Molécules, UMR CNRS 8523, Université de Lille 1, 59655 Villeneuve d'Ascq Cedex, France
| | - B Tercero
- Grupo de Astrofísica Molecular, Instituto de Ciencias de Materiales de Madrid (ICMM-CSIC). C/ Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049 Madrid, Spain
| | - J Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Ciencias de Materiales de Madrid (ICMM-CSIC). C/ Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049 Madrid, Spain
| | - R A Motiyenko
- Laboratoire de Physique des Lasers, Atomes et Molécules, UMR CNRS 8523, Université de Lille 1, 59655 Villeneuve d'Ascq Cedex, France
| | - L Margulès
- Laboratoire de Physique des Lasers, Atomes et Molécules, UMR CNRS 8523, Université de Lille 1, 59655 Villeneuve d'Ascq Cedex, France
| | - J-C Guillemin
- Institut des Sciences Chimiques de Rennes, Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex 7, France
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Kolesniková L, Alonso JL, Bermúdez C, Alonso ER, Tercero B, Cernicharo J, Guillemin JC. The millimeter wave spectrum of methyl cyanate: a laboratory study and astronomical search in space<sup/>. Astron Astrophys 2016; 591:A75. [PMID: 27721514 PMCID: PMC5055117 DOI: 10.1051/0004-6361/201628140] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
AIMS The recent discovery of methyl isocyanate (CH3NCO) in Sgr B2(N) and Orion KL makes methyl cyanate (CH3OCN) a potential molecule in the interstellar medium. The aim of this work is to fulfill the first requirement for its unequivocal identification in space, i.e. the availability of transition frequencies with high accuracy. METHODS The room-temperature rotational spectrum of methyl cyanate was recorded in the millimeter wave domain from 130 to 350 GHz. All rotational transitions revealed A-E splitting owing to methyl internal rotation and were globally analyzed using the ERHAM program. RESULTS The data set for the ground torsional state of methyl cyanate exceeds 700 transitions within J″ = 10 - 35 and [Formula: see text] and newly derived spectroscopic constants reproduce the spectrum close to the experimental uncertainty. Spectral features of methyl cyanate were then searched for in Orion KL, Sgr B2(N), B1-b, and TMC-1 molecular clouds. Upper limits to the column density of methyl cyanate are provided.
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Affiliation(s)
- L Kolesniková
- Grupo de Espectroscopía Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, 47011 Valladolid, Spain
| | - J L Alonso
- Grupo de Espectroscopía Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, 47011 Valladolid, Spain
| | - C Bermúdez
- Grupo de Espectroscopía Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, 47011 Valladolid, Spain
| | - E R Alonso
- Grupo de Espectroscopía Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, 47011 Valladolid, Spain
| | - B Tercero
- Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Spain
| | - J Cernicharo
- Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Spain
| | - J-C Guillemin
- Institut des Sciences Chimiques de Rennes, École Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex 7, France
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Cazzoli G, Lattanzi V, Kirsch T, Gauss J, Tercero B, Cernicharo J, Puzzarini C. Laboratory measurements and astronomical search for the HSO radical. Astron Astrophys 2016; 591:A126. [PMID: 27721513 PMCID: PMC5055096 DOI: 10.1051/0004-6361/201628745] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
CONTEXT Despite the fact that many sulfur-bearing molecules, ranging from simple diatomic species up to astronomical complex molecules, have been detected in the interstellar medium, the sulfur chemistry in space is largely unknown and a depletion in the abundance of S-containing species has been observed in the cold, dense interstellar medium (ISM). The chemical form of the missing sulfur has yet to be identified. AIMS For these reasons, in view of the fact that there is a large abundance of triatomic species harbouring sulfur, oxygen, and hydrogen, we decided to investigate the HSO radical in the laboratory to try its astronomical detection. METHODS High-resolution measurements of the rotational spectrum of the HSO radical were carried out within a frequency range well up into the THz region. Subsequently, a rigorous search for HSO in the two most studied high-mass star-forming regions, Orion KL and Sagittarius (Sgr) B2, and in the cold dark cloud Barnard 1 (B1-b) was performed. RESULTS The frequency coverage and the spectral resolution of our measurements allowed us to improve and extend the existing dataset of spectroscopic parameters, thus enabling accurate frequency predictions up to the THz range. These were used to derive the synthetic spectrum of HSO, by means of the MADEX code, according to the physical parameters of the astronomical source under consideration. For all sources investigated, the lack of HSO lines above the confusion limit of the data is evident. CONCLUSIONS The derived upper limit to the abundance of HSO clearly indicates that this molecule does not achieve significant abundances in either the gas phase or in the ice mantles of dust grains.
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Affiliation(s)
- Gabriele Cazzoli
- Dipartimento di Chimica "Giacomo Ciamician", Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy
| | - Valerio Lattanzi
- Dipartimento di Chimica "Giacomo Ciamician", Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy; Max-Planck-Institut für Extraterrestrische Physik, Giessenbachstraße 1, D-85748 Garching, Germany
| | - Till Kirsch
- Institut für Physikalische Chemie, Universität Mainz, D-55099 Mainz, Germany
| | - Jürgen Gauss
- Institut für Physikalische Chemie, Universität Mainz, D-55099 Mainz, Germany
| | - Belén Tercero
- Grupo de Astrofísica Molecular. Instituto de CC. de Materiales de Madrid (ICMM-CSIC). Sor Juana Inés de la Cruz 3, Cantoblanco, 28049 Madrid, Spain
| | - José Cernicharo
- Grupo de Astrofísica Molecular. Instituto de CC. de Materiales de Madrid (ICMM-CSIC). Sor Juana Inés de la Cruz 3, Cantoblanco, 28049 Madrid, Spain
| | - Cristina Puzzarini
- Dipartimento di Chimica "Giacomo Ciamician", Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy
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Agúndez M, Cernicharo J, Quintana-Lacaci G, Prieto LV, Castro-Carrizo A, Marcelino N, Guélin M. THE PECULIAR DISTRIBUTION OF CH 3CN IN IRC +10216 SEEN BY ALMA. Astrophys J 2015; 814:143. [PMID: 26709313 PMCID: PMC4688943 DOI: 10.1088/0004-637x/814/2/143] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
IRC +10216 is a circumstellar envelope around a carbon-rich evolved star which contains a large variety of molecules. According to interferometric observations, molecules are distributed either concentrated around the central star or as a hollow shell with a radius of ~15″. We present ALMA Cycle 0 band 6 observations of the J = 14 - 13 rotational transition of CH3CN in IRC +10216, obtained with an angular resolution of [Formula: see text]. The bulk of the emission is distributed as a hollow shell located at just ~2″ from the star, with a void of emission in the central region up to a radius of ~1″. This spatial distribution is markedly different from those found to date in this source for other molecules. Our analysis indicate that methyl cyanide is not formed neither in the stellar photosphere nor far in the outer envelope, but at radial distances as short as 1-2″, reaching a maximum abundance of ~ 0.02 molecules cm-3 at 2″ from the star. Standard chemical models of IRC +10216 predict that the bulk of CH3CN molecules should be present at a radius of ~ 15″, where other species such as polyyne radicals and cyanopolyynes are observed, with an additional inner component within 1″ from the star. The non-uniform structure of the circumstellar envelope and grain surface processes are discussed as possible causes of the peculiar distribution of methyl cyanide in IRC +10216.
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Affiliation(s)
- M Agúndez
- Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Spain
| | - J Cernicharo
- Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Spain
| | - G Quintana-Lacaci
- Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Spain
| | - L Velilla Prieto
- Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Spain
| | - A Castro-Carrizo
- Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, 38406 St. Martin d'Héres, France
| | - N Marcelino
- INAF, Istituto di Radioastronomia, via Gobetti 101, 40129 Bologna, Italy
| | - M Guélin
- Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, 38406 St. Martin d'Héres, France
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Fonfría JP, Cernicharo J, Richter MJ, Fernández-López M, Prieto LV, Lacy JH. The abundance of 28Si 32S, 29Si 32S, 28Si 34S, and 30Si 32S in the inner layers of the envelope of IRC+10216. Mon Not R Astron Soc 2015; 453:439-449. [PMID: 26997679 PMCID: PMC4797415 DOI: 10.1093/mnras/stv1634] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We present high spectral resolution mid-IR observations of SiS towards the C-rich AGB star IRC+10216 carried out with the Texas Echelon-cross-Echelle Spectrograph mounted on the NASA Infrared Telescope Facility. We have identified 204 ro-vibrational lines of 28Si32S, 26 of 29Si32S, 20 of 28Si34S, and 15 of 30Si32S in the frequency range 720 - 790 cm-1. These lines belong to bands v = 1 - 0, 2 - 1, 3 - 2, 4-3, and 5-4, and involve rotational levels with Jlow ≲ 90. About 30 per cent of these lines are unblended or weakly blended and can be partially or entirely fitted with a code developed to model the mid-IR emission of a spherically symmetric circumstellar envelope composed of expanding gas and dust. The observed lines trace the envelope at distances to the star ≲ 35R⋆(≃ 0″.7). The fits are compatible with an expansion velocity of 1+2.5(r/R⋆ -1) km s-1 between 1 and 5R⋆, 11 km s-1 between 5 and 20R⋆, and 14.5 km s-1 outwards. The derived abundance profile of 28Si32S with respect to H2 is 4.9 × 10-6 between the stellar photosphere and 5R⋆, decreasing linearly down to 1.6 × 10-6 at 20R⋆ and to 1.3 × 10-6 at 50R⋆. 28Si32S seems to be rotationally under LTE in the region of the envelope probed with our observations and vibrationally out of LTE in most of it. There is a red-shifted emission excess in the 28Si32S lines of band v = 1 - 0 that cannot be found in the lines of bands v = 2 - 1, 3 - 2, 4 - 3, and 5 - 4. This excess could be explained by an enhancement of the vibrational temperature around 20R⋆ behind the star. The derived isotopic ratios 28Si/29Si, and 32S/34S are 17 and 14, compatible with previous estimates.
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Affiliation(s)
- J. P. Fonfría
- Departamento de Estrellas y Medio Interestelar, Instituto de Astronomía, UNAM, Ciudad Universitaria, 04510, Mexico City (Mexico)
| | - J. Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049, Cantoblanco, Madrid (Spain)
| | - M. J. Richter
- Physics Dept. - UC Davis, One Shields Ave., Davis, CA 95616 (USA)
| | - M. Fernández-López
- Instituto Argentino de Radioastronomía, CCT-La Plata (CONICET), C.C.5, 1894, Villa Elisa (Argentina)
| | - L. Velilla Prieto
- Grupo de Astrofísica Molecular, Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049, Cantoblanco, Madrid (Spain)
| | - J. H. Lacy
- Astronomy Dept., University of Texas, Austin, TX 78712 (USA)
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Agúndez M, Cernicharo J, de Vicente P, Marcelino N, Roueff E, Fuente A, Gerin M, Guélin M, Albo C, Barcia A, Barbas L, Bolaño R, Colomer F, Diez MC, Gallego JD, Gómez-González J, López-Fernández I, López-Fernández JA, López-Pérez JA, Malo I, Serna JM, Tercero F. Probing non polar interstellar molecules through their protonated form: Detection of protonated cyanogen (NCCNH +). Astron Astrophys 2015; 579:L10. [PMID: 26543239 PMCID: PMC4630856 DOI: 10.1051/0004-6361/201526650] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Cyanogen (NCCN) is the simplest member of the series of dicyanopolyynes. It has been hypothesized that this family of molecules can be important constituents of interstellar and circumstellar media, although the lack of a permanent electric dipole moment prevents its detection through radioastronomical techniques. Here we present the first solid evidence of the presence of cyanogen in interstellar clouds through the detection of its protonated form toward the cold dark clouds TMC-1 and L483. Protonated cyanogen (NCCNH+) has been identified through the J = 5 - 4 and J = 10 - 9 rotational transitions using the 40m radiotelescope of Yebes and the IRAM 30m telescope. We derive beam averaged column densities for NCCNH+ of (8.6 ± 4.4) × 1010 cm-2 in TMC-1 and (3.9 ± 1.8) × 1010 cm-2 in L483, which translate to fairly low fractional abundances relative to H2, in the range (1-10) × 10-12. The chemistry of protonated molecules in dark clouds is discussed, and it is found that, in general terms, the abundance ratio between the protonated and non protonated forms of a molecule increases with increasing proton affinity. Our chemical model predicts an abundance ratio NCCNH+/NCCN of ~ 10-4, which implies that the abundance of cyanogen in dark clouds could be as high as (1-10) × 10-8 relative to H2, i.e., comparable to that of other abundant nitriles such as HCN, HNC, and HC3N.
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Affiliation(s)
- M Agúndez
- Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Spain
| | - J Cernicharo
- Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Spain
| | - P de Vicente
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales(CNTRAG), Observatorio de Yebes (IGN), Spain
| | - N Marcelino
- INAF, Istituto di Radioastronomia, via P. Gobetti 101, 40129 Bologna, Italy
| | - E Roueff
- LERMA, Observatoire de Paris, PSL Research University, CNRS, UMR8112, Place Janssen, 92190 Meudon Cedex, France
| | - A Fuente
- Observatorio Astronómico Nacional (OAN), Calle Alfonso XII, No 3, 28014 Madrid, Spain
| | - M Gerin
- LERMA, Observatoire de Paris, École Normale Supérieure, PSL Research University, CNRS, UMR8112, F-75014, Paris, France
| | - M Guélin
- Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, 38406 St. Martin d'Héres, France
| | - C Albo
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales(CNTRAG), Observatorio de Yebes (IGN), Spain
| | - A Barcia
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales(CNTRAG), Observatorio de Yebes (IGN), Spain
| | - L Barbas
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales(CNTRAG), Observatorio de Yebes (IGN), Spain
| | - R Bolaño
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales(CNTRAG), Observatorio de Yebes (IGN), Spain
| | - F Colomer
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales(CNTRAG), Observatorio de Yebes (IGN), Spain
| | - M C Diez
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales(CNTRAG), Observatorio de Yebes (IGN), Spain
| | - J D Gallego
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales(CNTRAG), Observatorio de Yebes (IGN), Spain
| | - J Gómez-González
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales(CNTRAG), Observatorio de Yebes (IGN), Spain
| | - I López-Fernández
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales(CNTRAG), Observatorio de Yebes (IGN), Spain
| | - J A López-Fernández
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales(CNTRAG), Observatorio de Yebes (IGN), Spain
| | - J A López-Pérez
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales(CNTRAG), Observatorio de Yebes (IGN), Spain
| | - I Malo
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales(CNTRAG), Observatorio de Yebes (IGN), Spain
| | - J M Serna
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales(CNTRAG), Observatorio de Yebes (IGN), Spain
| | - F Tercero
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales(CNTRAG), Observatorio de Yebes (IGN), Spain
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Prieto LV, Cernicharo J, Quintana-Lacaci G, Agúndez M, Castro-Carrizo A, Fonfŕia JP, Marcelino N, Zúñiga J, Requena A, Bastida A, Lique F, Guélin M. SI-BEARING MOLECULES TOWARD IRC+10216: ALMA UNVEILS THE MOLECULAR ENVELOPE OF CWLEO. Astrophys J Lett 2015; 805:L13. [PMID: 26688711 PMCID: PMC4681092 DOI: 10.1088/2041-8205/805/2/l13] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We report the detection of SiS rotational lines in high-vibrational states as well as SiO and SiC2 lines in their ground vibrational state toward IRC+10216 during the Atacama Large Millimeter Array Cycle 0. The spatial distribution of these molecules shows compact emission for SiS and a more extended emission for SiO and SiC2, and also proves the existence of an increase in the SiC2 emission at the outer shells of the circumstellar envelope. We analyze the excitation conditions of the vibrationally excited SiS using the population diagram technique, and we use a large velocity gradient model to compare with the observations. We found moderate discrepancies between the observations and the models that could be explained if SiS lines detected are optically thick. Additionally, the line profiles of the detected rotational lines in the high energy vibrational states show a decreasing linewidth with increasing energy levels. This may be evidence that these lines could be excited only in the inner shells, i.e., the densest and hottest, of the circumstellar envelope of IRC+10216.
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Affiliation(s)
- L Velilla Prieto
- Group of Molecular Astrophysics. ICMM, CSIC. C/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain ; Centro de Astrobiología, INTA-CSIC. E-28691 Villanueva de la Cañada, Madrid, Spain
| | - J Cernicharo
- Group of Molecular Astrophysics. ICMM, CSIC. C/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
| | - G Quintana-Lacaci
- Group of Molecular Astrophysics. ICMM, CSIC. C/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
| | - M Agúndez
- Group of Molecular Astrophysics. ICMM, CSIC. C/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
| | - A Castro-Carrizo
- Institut de Radioastronomie Millimétrique. 300 rue de la la Piscine, F-38406, Saint Martin d'Hères, France
| | - J P Fonfŕia
- Departamento de Estrellas y Medio Interestelar, Instituto de Astronomía, Universidad Nacional Autónoma de México (UNAM). Ciudad Universitaria, 04510, Mexico City, México
| | - N Marcelino
- Istituto di Radiastronomia, INAF-CNR, via Gobetti 101, 40129 Bologna, Italy
| | - J Zúñiga
- Departamento de Química Física, Facultad de Química, Universidad de Murcia. Campus Espinardo, 30100 Murcia, Spain
| | - A Requena
- Departamento de Química Física, Facultad de Química, Universidad de Murcia. Campus Espinardo, 30100 Murcia, Spain
| | - A Bastida
- Departamento de Química Física, Facultad de Química, Universidad de Murcia. Campus Espinardo, 30100 Murcia, Spain
| | - F Lique
- LOMC-UMR 6294, CNRS-Université du Havre, 25 rue Philippe Lebon, BP. 1123, 76063 Le Havre cedex, France
| | - M Guélin
- Institut de Radioastronomie Millimétrique. 300 rue de la la Piscine, F-38406, Saint Martin d'Hères, France ; LERMA, Observatoire de Paris, PSL Research University, CNRS, UMR 8112, F-75014, Paris, France
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Abstract
We have conducted radioastronomical observations of 9 dark clouds with the IRAM 30m telescope. We present the first identification in space of the ketenyl radical (HCCO) toward the starless core Lupus-1A and the molecular cloud L483, and the detection of the related molecules ketene (H2CCO) and acetaldehyde (CH3CHO) in these two sources and 3 additional dark clouds. We also report the detection of the formyl radical (HCO) in the 9 targeted sources and of propylene (CH2CHCH3) in 4 of the observed sources, which extends significantly the number of dark clouds where these molecules are known to be present. We derive a beam-averaged column density of HCCO of ~ 5 × 1011 cm-2 in both Lupus-1A and L483, which means that the ketenyl radical is just ~10 times less abundant than ketene in these sources. The non-negligible abundance of HCCO found implies that there must be a powerful formation mechanism able to counterbalance the efficient destruction of this radical through reactions with neutral atoms. The column densities derived for HCO, (0.5-2.7) ×1012 cm-2, and CH2CHCH3, (1.9-4-2) ×1013 cm-2, are remarkably uniform across the sources where these species are detected, confirming their ubiquity in dark clouds. Gas phase chemical models of cold dark clouds can reproduce the observed abundances of HCO, but cannot explain the presence of HCCO in Lupus-1A and L483 and the high abundances derived for propylene. The chemistry of cold dark clouds needs to be revised in the light of these new observational results.
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Affiliation(s)
- Marcelino Agúndez
- Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Spain
| | - José Cernicharo
- Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Spain
| | - Michel Guélin
- Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, 38406 St. Martin d'Héres, France
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Puzzarini C, Ali A, Biczysko M, Barone V. ACCURATE SPECTROSCOPIC CHARACTERIZATION OF PROTONATED OXIRANE: A POTENTIAL PREBIOTIC SPECIES IN TITAN'S ATMOSPHERE. Astrophys J 2014; 792:118. [PMID: 26543241 PMCID: PMC4630863 DOI: 10.1088/0004-637x/792/2/118] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
An accurate spectroscopic characterization of protonated oxirane has been carried out by means of state-of-the-art computational methods and approaches. The calculated spectroscopic parameters from our recent computational investigation of oxirane together with the corresponding experimental data available were used to assess the accuracy of our predicted rotational and IR spectra of protonated oxirane. We found an accuracy of about 10 cm-1 for vibrational transitions (fundamentals as well as overtones and combination bands) and, in relative terms, of 0.1% for rotational transitions. We are therefore confident that the spectroscopic data provided herein are a valuable support for the detection of protonated oxirane not only in Titan's atmosphere but also in the interstellar medium.
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Affiliation(s)
- Cristina Puzzarini
- Dipartimento di Chimica "Giacomo Ciamician," Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy;
| | - Ashraf Ali
- NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
| | - Malgorzata Biczysko
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy ; Consiglio Nazionale delle Ricerche, Istituto di Chimica dei Composti OrganoMetallici (ICCOM-CNR), UOS di Pisa, Area della Ricerca CNR, Via G. Moruzzi 1, I-56124 Pisa, Italy
| | - Vincenzo Barone
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy
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Puzzarini C, Biczysko M, Bloino J, Barone V. ACCURATE SPECTROSCOPIC CHARACTERIZATION OF OXIRANE: A VALUABLE ROUTE TO ITS IDENTIFICATION IN TITAN'S ATMOSPHERE AND THE ASSIGNMENT OF UNIDENTIFIED INFRARED BANDS. Astrophys J 2014; 785:107. [PMID: 26543240 PMCID: PMC4630858 DOI: 10.1088/0004-637x/785/2/107] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In an effort to provide an accurate spectroscopic characterization of oxirane, state-of-the-art computational methods and approaches have been employed to determine highly accurate fundamental vibrational frequencies and rotational parameters. Available experimental data were used to assess the reliability of our computations, and an accuracy on average of 10 cm-1 for fundamental transitions as well as overtones and combination bands has been pointed out. Moving to rotational spectroscopy, relative discrepancies of 0.1%, 2%-3%, and 3%-4% were observed for rotational, quartic, and sextic centrifugal-distortion constants, respectively. We are therefore confident that the highly accurate spectroscopic data provided herein can be useful for identification of oxirane in Titan's atmosphere and the assignment of unidentified infrared bands. Since oxirane was already observed in the interstellar medium and some astronomical objects are characterized by very high D/H ratios, we also considered the accurate determination of the spectroscopic parameters for the mono-deuterated species, oxirane-d1. For the latter, an empirical scaling procedure allowed us to improve our computed data and to provide predictions for rotational transitions with a relative accuracy of about 0.02% (i.e., an uncertainty of about 40 MHz for a transition lying at 200 GHz).
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Affiliation(s)
- Cristina Puzzarini
- Dipartimento di Chimica "Giacomo Ciamician," Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy;
| | - Malgorzata Biczysko
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy ; Consiglio Nazionale delle Ricerche, Istituto di Chimica dei Composti OrganoMetallici (ICCOM-CNR), UOS di Pisa, Area della Ricerca CNR, Via G. Moruzzi 1, I-56124 Pisa, Italy
| | - Julien Bloino
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy ; Consiglio Nazionale delle Ricerche, Istituto di Chimica dei Composti OrganoMetallici (ICCOM-CNR), UOS di Pisa, Area della Ricerca CNR, Via G. Moruzzi 1, I-56124 Pisa, Italy
| | - Vincenzo Barone
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy
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