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Roy T, Satpati S, Sinjari A, Anoop A, Thimmakondu VS, Ghosal S. Energetic and Spectroscopic Properties of Astrophysically Relevant MgC 4H Radicals Using High-Level Ab Initio Calculations. J Phys Chem A 2024; 128:1466-1476. [PMID: 38364260 DOI: 10.1021/acs.jpca.3c06828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2024]
Abstract
Considering the importance of magnesium-bearing hydrocarbon molecules (MgCnH; n = 2, 4, and 6) in the carbon-rich circumstellar envelopes (e.g., IRC+10216), a total of 28 constitutional isomers of MgC4H have been theoretically investigated using density functional theory (DFT) and coupled-cluster methods. The zero-point vibrational energy corrected relative energies at the ROCCSD(T)/cc-pCVTZ level of theory reveal that the linear isomer, 1-magnesapent-2,4-diyn-1-yl (1, 2Σ+), is the global minimum geometry on the MgC4H potential energy surface. The latter has been detected both in the laboratory and in the evolved carbon star, IRC+10216. The calculated spectroscopic data for 1 match well with the experimental observations (error ∼ 0.78%) which validates our theoretical methodology. Plausible isomerization processes happening among different isomers are examined using DFT and coupled-cluster methods. CASPT2 calculations have been performed for a few isomers exhibiting multireference characteristics. The second most stable isomer, 1-ethynyl-1λ3-magnesacycloprop-2-ene-2,3-diyl (2, 2A1, μ = 2.54 D), is 146 kJ mol-1 higher in energy than 1 and possibly the next promising candidate to be detected in the laboratory or in the interstellar medium in future.
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Affiliation(s)
- Tarun Roy
- Department of Chemistry, National Institute of Technology Durgapur, M G Avenue, Durgapur, West Bengal 713209, India
| | - Sayon Satpati
- Department of Chemistry, National Institute of Technology Durgapur, M G Avenue, Durgapur, West Bengal 713209, India
| | - Aland Sinjari
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, California 92182-1030, United States
- Nuclear Science Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, United States
| | - Anakuthil Anoop
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
| | - Venkatesan S Thimmakondu
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, California 92182-1030, United States
| | - Subhas Ghosal
- Department of Chemistry, National Institute of Technology Durgapur, M G Avenue, Durgapur, West Bengal 713209, India
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2
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Wang L, Jiang X, Trabelsi T, Wang G, Francisco JS, Zeng X, Zhou M. Spectroscopic Study of [Mg, H, N, C, O] Species: Implications for the Astrochemical Magnesium Chemistry. J Am Chem Soc 2024; 146:4162-4171. [PMID: 38306246 DOI: 10.1021/jacs.3c13144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2024]
Abstract
Magnesium is an abundant metal element in space, and magnesium chemistry has vital importance in the evolution of interstellar medium (ISM) and circumstellar regions, such as the asymptotic giant branch star IRC+10216 where a variety of Mg compounds bearing H, C, N, and O have been detected and proposed as the important components in the gas-phase molecular clouds and solid-state dust grains. Herein, we report the formation and infrared spectroscopic characterization of the Mg-bearing molecules HMg, [Mg, N, C], [Mg, H, N, C], [Mg, N, C, O], and [Mg, H, N, C, O] from the reactions of Mg/Mg+ and the prebiotic isocyanic acid (HNCO) in the solid neon matrix. Based on their thermal diffusion and photochemical behavior, a complex reactivity landscape involving association, decomposition, and isomerization reactions of these Mg-bearing molecules is developed, which can not only help understand the chemical processes of the magnesium (iso)cyanides in astrochemistry but also provide implications on the presence of magnesium (iso)cyanates in the ISM and the chemical model for the dust grain surface reactions. It also provides a new paradigm of the key intermediate nature of the cationic complexes in the formation of neutral interstellar species.
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Affiliation(s)
- Lina Wang
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200438, China
| | - Xin Jiang
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200438, China
| | - Tarek Trabelsi
- Department of Earth and Environment Science, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6243, United States
| | - Guanjun Wang
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200438, China
| | - Joseph S Francisco
- Department of Earth and Environment Science, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6243, United States
| | - Xiaoqing Zeng
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200438, China
| | - Mingfei Zhou
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200438, China
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González-Sánchez L, Sathyamurthy N, Gianturco FA. The role of small molecular cations in the chemical flow of the interstellar environments. Phys Chem Chem Phys 2023; 25:23370-23383. [PMID: 37614146 DOI: 10.1039/d3cp03000h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Abstract
Molecular ions have been ubiquitous in a variety of environments in the interstellar medium, from Circumstellar Envelopes to Dark Molecular Clouds and to Diffuse Clouds. Their role in the multitude of molecular processes which have been found to occur in those environments has been the subject of many studies over the years, so that we have acquired by now a complex body of data on their chemical structures, their possible function within chemical reactions and their most likely paths to formation. In the present work we review a broad range of such molecular ions, focusing exclusively on positive ions involving the smallest and simplest cations which have been either detected or conjectured as present in the interstellar medium (ISM). We therefore consider mainly molecular cations formed with components like H, H+, He and He+, atomic species which are by far the most abundant baryons in the ISM in general. Their likely structures and their roles in a variety of chemical energy flow paths are discussed and presented within the context of their interstellar environments.
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Affiliation(s)
- Lola González-Sánchez
- Departamento de Química Física, University of Salamanca, Plaza de los Caídos sn, 37008 Salamanca, Spain.
| | - N Sathyamurthy
- Indian Institute of Science Education and Research Mohali, SAS Nagar, Punjab 140306, India
| | - Francesco A Gianturco
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, 6020, Innsbruck, Austria
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4
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Woon DE. Icy Grain Mantle Surface Astrochemistry of MgNC: The Emergence of Metal Ion Catalysis Studied via Model Ice Cluster Calculations. J Phys Chem A 2022; 126:5186-5194. [PMID: 35895034 DOI: 10.1021/acs.jpca.2c01739] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
One of a small number of known magnesium-containing astromolecules, magnesium isocyanide (MgNC) was first detected in 1986. MgNC is an intriguing reactant to consider: it is an open-shell radical in which its metal atom forms a bond with CN that is a mixture of ionic and covalent character. While its gas phase astrochemistry has received prior attention, the grain surface chemistry of MgNC has never been studied. Because of its ionic character, MgNC is found to interact far more strongly with an ice surface than molecules with a greater degree of covalency. As a radical, it may react with closed-shell molecules deposited from the gas phase. In this work, cluster calculations treated with density functional theory and correlation consistent basis sets were used to model the deposition of MgNC on clusters containing 17 and 24 water molecules, which were then allowed to react with acetylene (HCCH) and hydrogen cyanide (HCN) as well as with H atoms. The addition of H to MgNC-nH2O yields hydromagnesium isocyanide (HMgNC), a known astromolecule that may be ejected into the gas phase. HCCH and HCN bind to MgNC-nH2O to form intermediate radical compounds that may then also react with H atoms. There is enough reaction energy from H addition to eject fragments of the intermediates into the gas phase: the vinyl radical (C2H3) for HCCH and the methaniminyl radical (H2CN) for HCN. That leaves MgNC-nH2O to perform further catalytic activity. Alternatively, various hydrogenated divalent Mg compounds may also be stabilized and frozen into the ice or potentially ejected into the gas phase. Benchmark coupled cluster theory calculations in limited systems were used to characterize the submerged reaction barriers present when HCCH or HCN add to MgNC in the gas phase.
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Affiliation(s)
- David E Woon
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
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Panda S, Sivadasan D, Job N, Sinjari A, Thirumoorthy K, Anoop A, Thimmakondu VS. Why Are MgC 3H Isomers Missing in the Interstellar Medium? J Phys Chem A 2022; 126:4465-4475. [PMID: 35767462 PMCID: PMC9382639 DOI: 10.1021/acs.jpca.2c02220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Considering the recent findings of linear doublet (2Σ+) MgCnH isomers (n = 2, 4, and 6) in the evolved carbon star IRC+10216, various structural isomers of MgC3H and MgC3H+ are theoretically investigated here. For MgC3H, 11 doublet and 8 quartet stationary points ranging from 0.0 to 71.8 and 0.0 to 110.1 kcal mol-1, respectively, have been identified initially at the UωB97XD/6-311++G(2d,2p) level. To get accurate relative energies, further energy evaluations are carried out for all isomers with coupled cluster methods and thermochemical modules such as G3//B3LYP, G4MP2, and CBS-QB3 methods. Unlike the even series, where the global minima are linear molecules with a Mg atom at one end, in the case of MgC3H, the global minimum geometry turns out to be a cyclic isomer, 2-magnesabicyclo[1.1.0]but-1,3,4-triyl (1, C2v, 2A1). In addition, five low-lying isomers, magnesium-substituted cyclopropenylidene (2, Cs, 2A'), 1-magnesabut-2,3-dien-1-yl-4-ylidene (3, Cs, 2A″), 1-magnesabut-2-yn-1-yl-4-ylidene (4, Cs, 2A″), 2λ3-magnesabicyclo[1.1.0]but-1,3-diyl-4-ylidene (5, C2v;, 2A1), and 1-magnesabut-2,3-dien-2-yl-4-ylidene (6, C∞v, 2Σ+), were also identified. The doublet linear isomer of MgC3H, 1-magnesabutatrienyl (10, C∞v, 2Σ+) turns out to be a minimum but lies 54.1 kcal mol-1 above 1 at the ROCCSD(T)/cc-pVTZ level. The quartet (4Σ+) electronic state of 10 was also found to be a minimum, but it lies 8.0 kcal mol-1 above 1 at the same level. Among quartets, isomer 10 is the most stable molecule. The next quartet electronic state (of isomer 11) is 34.4 kcal mol-1 above 10, and all other quartet electronic states of other isomers are not energetically close to low-lying doublet isomers 2 to 6. Overall, the chemical space of MgC3H contains more cyclic isomers (1, 2, and 3) on the low-energy side unlike their even-numbered MgCnH counterparts (n = 2, 4, and 6). Though the quartet electronic state of 10 is linear, it is not the global minimum geometry on the MgC3H potential energy surface. Isomerization pathways among the low-lying isomers (doublets of 1-4 and a quartet of 10) reveal that these molecules are kinetically stable. For the cation, MgC3H+, the cyclic isomers (1+, 2+, and 3+) are on the low-energy side. The singlet linear isomer, 10+, is a fourth-order saddle point. The low-lying cations are quite polar, with dipole moment values of >7.00 D. The current theoretical data would be helpful to both laboratory astrophysicists and radioastronomers for further studies on the MgC3H0/+ isomers.
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Affiliation(s)
- Sunanda Panda
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721 302, West Bengal, India
| | - Devipriya Sivadasan
- Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore 632 014, Tamil Nadu, India
| | - Nisha Job
- Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore 632 014, Tamil Nadu, India
| | - Aland Sinjari
- School of Mathematics, Biological, Exercise & Physical Sciences, San Diego Miramar College, San Diego, California 92126-2910, United States
| | - Krishnan Thirumoorthy
- Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore 632 014, Tamil Nadu, India
| | - Anakuthil Anoop
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721 302, West Bengal, India
| | - Venkatesan S Thimmakondu
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, California 92182-1030, United States
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Agbaglo DA, Cheng Q, Fortenberry RC, Stanton JF, DeYonker NJ. Theoretical Rovibrational Spectroscopy of Magnesium Tricarbide-Multireference Character Thwarts a Full Analysis of All Isomers. J Phys Chem A 2022; 126:4132-4146. [PMID: 35758849 DOI: 10.1021/acs.jpca.2c01340] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Magnesium tricarbide isomers are studied herein with coupled cluster theory and multireference configuration interaction to support their possible detection in astrochemical environments such as the circumstellar envelope surrounding the star IRC +10216 or in terrestrial laboratories. Magnesium-bearing species may abound in the interstellar medium (ISM), but only eight (MgNC, MgCN, HMgNC, MgC2H, MgC3N, MgC4H, MgC5N, and MgC6H) have been directly identified thus far. Several possible isomers for the related MgC3 system are explored in their singlet and triplet spin multiplicities. Overall, this work offers quantum chemical insight of rovibrational spectroscopic data for MgC3 using quartic force fields (QFFs) based on the CCSD(T) and CCSD(T)-F12 levels of theory at the complete basis set (CBS) limit. Additional corrections with small basis set CCSDT(Q) and scalar relativistic effects are also included in the analysis. Salient multireference character is found in the singlet diamond electronic state, which makes a definitive assignment of the ground state challenging. Nevertheless, coupled cluster-based composite energies and multireference configuration interaction both predict that the 1A1 diamond isomer is 1.6-2.2 kcal mol-1 lower in energy than the 3A1 diamond isomer. Furthermore, highly accurate binding energies of various isomers MgC3 are provided for comparison to photodetachment experiments. Dipole moments along with harmonic infrared intensities will guide efforts for astronomical and spectroscopic characterization.
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Affiliation(s)
- Donatus A Agbaglo
- Department of Chemistry, University of Memphis, Memphis, Tennessee 38151, United States
| | - Qianyi Cheng
- Department of Chemistry, University of Memphis, Memphis, Tennessee 38151, United States
| | - Ryan C Fortenberry
- Department of Chemistry & Biochemistry, University of Mississippi, University, Mississippi 38677-1848, United States
| | - John F Stanton
- Department of Chemistry and Physics, University of Florida, Gainesville, Florida 32611, United States
| | - Nathan J DeYonker
- Department of Chemistry, University of Memphis, Memphis, Tennessee 38151, United States
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Cabezas C, Peña I, Saragi RT, Juanes M, Lesarri A, Cernicharo J. Rotational spectroscopy of the large saturated dinitriles hexanedinitrile and heptanedinitrile. Spectrochim Acta A Mol Biomol Spectrosc 2022; 270:120844. [PMID: 35007907 DOI: 10.1016/j.saa.2021.120844] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 12/08/2021] [Accepted: 12/29/2021] [Indexed: 06/14/2023]
Abstract
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 interstellar medium. In this work, two members of this family, hexanedinitrile and heptanedinitrile, have been investigated through their rotational spectra. The jet-cooled broadband chirped-pulse Fourier transform microwave spectra of both molecules were measured in the 2-8 GHz frequency region. Three and six conformers of hexanedinitrile and heptanedinitrile, respectively, were detected and assigned based on the rotational and quadrupole coupling constants.
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Affiliation(s)
- Carlos Cabezas
- Instituto de Física Fundamental (IFF-CSIC), Group of Molecular Astrophysics, C/ Serrano 121, Madrid 28006, Spain.
| | - Isabel Peña
- Departamento de Química Física y Química Inorgánica, Facultad de Ciencias, Universidad de Valladolid, Paseo de Belén 7, Valladolid 47011, Spain.
| | - Rizalina T Saragi
- Departamento de Química Física y Química Inorgánica, Facultad de Ciencias-I.U. CINQUIMA, Universidad de Valladolid, Paseo de Belén 7, Valladolid 47011, Spain
| | - Marcos Juanes
- Departamento de Química Física y Química Inorgánica, Facultad de Ciencias-I.U. CINQUIMA, Universidad de Valladolid, Paseo de Belén 7, Valladolid 47011, Spain
| | - Alberto Lesarri
- Departamento de Química Física y Química Inorgánica, Facultad de Ciencias-I.U. CINQUIMA, Universidad de Valladolid, Paseo de Belén 7, Valladolid 47011, Spain
| | - José Cernicharo
- Instituto de Física Fundamental (IFF-CSIC), Group of Molecular Astrophysics, C/ Serrano 121, Madrid 28006, Spain
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Bai J, Yu HT. Theoretical investigation of the structures, stabilities, and vibrational and rotational spectroscopic parameters of linear HOMgNC and HMgNCO molecules by density functional theory and coupled-cluster method. NEW J CHEM 2022. [DOI: 10.1039/d2nj00715k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Linear HOMgNC and HMgNCO molecules: two appropriate candidates for interstellar observation and experimental preparation.
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Affiliation(s)
- Jie Bai
- School of Chemistry and Materials Science, Heilongjiang University, Harbin, 150080, P. R. China
| | - Hai-Tao Yu
- School of Chemistry and Materials Science, Heilongjiang University, Harbin, 150080, P. R. China
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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, 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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11
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Cernicharo J, Cabezas C, Endo Y, Marcelino N, Agúndez M, Tercero B, Gallego JD, de Vicente P. Space and laboratory discovery of HC 3 S. Astron Astrophys 2021; 646:L3. [PMID: 33824540 PMCID: PMC7610522 DOI: 10.1051/0004-6361/202040013] [Citation(s) in RCA: 3] [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 report the detection in TMC-1 of the protonated form of C3S. The discovery of the cation HC3S+ was carried through the observation of four harmonically related lines in the Q band using the Yebes 40m radiotelescope, and is supported by accurate ab initio calculations and laboratory measurements of its rotational spectrum. We derive a column density N(HC3S+) = (2.0 ± 0.5) × 1011 cm-2, which translates to an abundance ratio C3S/HC3S+ of 65 ± 20. This ratio is comparable to the CS/HCS+ ratio (35 ± 8) and is a factor of about ten larger than the C3O/HC3O+ ratio previously found in the same source. However, the abundance ratio HC3O+/HC3S+ is 1.0 ± 0.5, while C3O/C3S is just ~ 0.11. We also searched for protonated C2S in TMC-1, based on ab initio calculations of its spectroscopic parameters, and derive a 3σ upper limit of N(HC2S+)≤ 9×1011 cm-2 and a C2S/HC2S+ ≥ 60. The observational results are compared with a state-of-the-art gas-phase chemical model and conclude that HC3S+ is mostly formed through several pathways: proton transfer to C3S, reaction of S+ with c-C3H2, and reaction between neutral atomic sulfur and the ion C3H+ 3.
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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
| | - Y Endo
- Department of Applied Chemistry, Science Building II, National Chiao Tung University, 1001 Ta-Hsueh Rd., Hsinchu 30010, Taiwan
| | - 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
- Observatorio Astronómico Nacional (IGN), C/ Alfonso XII, 3, 28014, Madrid, Spain
- 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
| | - P de Vicente
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, 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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Tercero F, López-Pérez JA, Gallego JD, Beltrán F, García O, Patino-Esteban M, López-Fernández I, Gómez-Molina G, Diez M, García-Carreño P, Malo I, Amils R, Serna JM, Albo C, Hernández JM, Vaquero B, González-García J, Barbas L, López-Fernández JA, Bujarrabal V, Gómez-Garrido M, Pardo JR, Santander-García M, Tercero B, Cernicharo J, de Vicente P. Yebes 40 m radio telescope and the broad band NANOCOSMOS receivers at 7 mm and 3 mm for line surveys. Astron Astrophys 2021; 645:A37. [PMID: 33408420 PMCID: PMC7116543 DOI: 10.1051/0004-6361/202038701] [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: 05/25/2023]
Abstract
CONTEXT Yebes 40m radio telescope is the main and largest observing instrument at Yebes Observatory and it is devoted to Very Long Baseline Interferometry (VLBI) and single dish observations since 2010. It has been covering frequency bands between 2 GHz and 90 GHz in discontinuous and narrow windows in most of the cases, to match the current needs of the European VLBI Network (EVN) and the Global Millimeter VLBI Array (GMVA). AIMS Nanocosmos project, a European Union funded synergy grant, opened the possibility to increase the instantaneous frequency coverage to observe many molecular transitions with single tunnings in single dish mode. This reduces the observing time and maximises the output from the telescope. METHODS We present the technical specifications of the recently installed 31.5 - 50GHz (Q band) and 72 - 90.5 GHz (W band) receivers along with the main characteristics of the telescope at these frequency ranges. We have observed IRC+10216, CRL 2688 and CRL 618, which harbour a rich molecular chemistry, to demonstrate the capabilities of the new instrumentation for spectral observations in single dish mode. RESULTS The results show the high sensitivity of the telescope in the Q band. The spectrum of IRC+10126 offers a signal to noise ratio never seen before for this source in this band. On the other hand, the spectrum normalised by the continuum flux towards CRL 618 in the W band demonstrates that the 40 m radio telescope produces comparable results to those from the IRAM 30 m radio telescope, although with a smaller sensitivity. The new receivers fulfil one of the main goals of Nanocosmos and open the possibility to study the spectrum of different astrophysical media with unprecedented sensitivity.
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Affiliation(s)
- 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
| | - F. Beltrán
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - O. García
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, 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
| | - G. Gómez-Molina
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - M. Diez
- 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
| | - 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. M. Serna
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - C. Albo
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J. M. Hernández
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - B. Vaquero
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J. González-García
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - L. Barbas
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | | | - V. Bujarrabal
- Observatorio Astronómico Nacional (IGN), C/ Alfonso XII, 3, 28014, Madrid, Spain
| | - M. Gómez-Garrido
- 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
- Instituto de Física Fundamental (IFF-CSIC). Group of Molecular Astrophysics, C/ Serrano 123, 28006 Madrid, Spain
| | - M. Santander-García
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
- Observatorio Astronómico Nacional (IGN), C/ Alfonso XII, 3, 28014, 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. Cernicharo
- Instituto de Física Fundamental (IFF-CSIC). Group of Molecular Astrophysics, C/ Serrano 123, 28006 Madrid, Spain
| | - P. de Vicente
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
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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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Pandey AP, Padidela UK, Thulasiraman LK, Sethu R, Vairaprakash P, Thimmakondu VS. MgC 6H 2 Isomers: Potential Candidates for Laboratory and Radioastronomical Studies. J Phys Chem A 2020; 124:7518-7525. [PMID: 32804506 DOI: 10.1021/acs.jpca.0c06401] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Eighty three stationary points of MgC6H2 isomers spanning from 0 to 215 kcal mol-1 have been theoretically identified using density functional theory at the B3LYP/6-311++G(2d,2p) level of theory. Among them, four low-lying isomers lying within 23.06 kcal mol-1 (1 eV) have been further characterized in detail using high-level coupled-cluster (CC) methods. The thermodynamically most stable isomer turns out to be 1-magnesacyclohepta-4-en-2,6-diyne (1). The other three isomers, 3-magnesahepta-1,4,6-triyne (2), 1-magnesacyclohepta-2,3,4-trien-6-yne (3), and 1-magnesahepta-2,4,6-triyne (4) lie 8.24, 19.76, and 21.36 kcal mol-1, respectively, above 1 at the ae-CCSD(T)/cc-pCVTZ level of theory. All the four isomers are polar with a permanent electric dipole moment (μ ≠ 0). Hence, they are potential candidates for rotational spectroscopic studies. Considering the recent identification of magnesium-bearing hydrocarbons such as, MgC2H and MgC4H in IRC+10216, it is believed that the current theoretical data may be of relevance to laboratory molecular spectroscopic and radioastronomical studies on MgC6H2 isomers. The energetic and spectroscopic information gathered in this study would aid the detection of low-lying MgC6H2 isomers in the laboratory, which are indispensable for radioastronomical studies. It is also noted here that neither the National Institute of Standards and Technology Chemistry WebBook nor the Kinetic Database for Astrochemistry lists any isomer of MgC6H2 at the moment. Therefore, these isomers are studied here theoretically for the very first time.
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Affiliation(s)
- Aditya P Pandey
- Electrical and Computer Engineering, College of Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States.,Department of Chemistry, Birla Institute of Technology and Science, Pilani, K K Birla Goa Campus, Goa - 403 726, India
| | - Uday Kumar Padidela
- Department of Chemistry, Birla Institute of Technology and Science, Pilani, K K Birla Goa Campus, Goa - 403 726, India
| | - Loganathan Konda Thulasiraman
- Department of Chemistry, Alagappa Chettiar Government College of Engineering and Technology, Karaikudi 630 003, Tamil Nadu, India
| | - Ramakrishnan Sethu
- Department of Microbiology, University of Illinois, 601 South Goodwin Avenue, Urbana, Illinois 61801, United States
| | - Pothiappan Vairaprakash
- Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur - 613 401, Tamil Nadu, India
| | - Venkatesan S Thimmakondu
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, California 92182-1030, United States
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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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Pardo JR, Bermúdez C, Cabezas C, Agúndez M, Gallego JD, Fonfría JP, Velilla-Prieto L, Quintana-Lacaci G, Tercero B, Guélin M, Cernicharo J. Detection of vibrationally excited HC 7N and HC 9N in IRC+10216 ⋆. Astron Astrophys 2020; 640:L13. [PMID: 33173233 PMCID: PMC7116341 DOI: 10.1051/0004-6361/202038571] [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: 05/31/2023]
Abstract
Observations of IRC +10216 with the Yebes 40m telescope between 31 and 50 GHz have revealed more than 150 unidentified lines. Some of them can be grouped into a new series of 26 doublets, harmonically related with integer quantum numbers ranging from J up=54 to 80. The separation of the doublets increases systematically with J, i.e., as expected for a linear species in one of its bending modes. The rotational parameters resulting from the fit to these data are B = 290.8844 ± 0.0004 MHz, D = 0.88 ± 0.04 Hz, q = 0.1463 ± 0.0001 MHz. The rotational constant is very close to that of the ground state of HC9N. Ab initio calculations show an excellent agreement between these parameters and those predicted for the lowest energy vibrationally excited state, ν 19=1, of HC9N. This is the first detection, and complete characterization in space, of vibrationally excited HC9N. An energy of 41.5 cm-1 is estimated for the ν 19 state. In addition, 17 doublets of HC7N in the ν 15=1 state, for which laboratory spectroscopy is available, have been detected for the first time in IRC+10216. Several doublets of HC5N in its ν 11=1 state have been also observed. The column density ratio between the ground and the lowest excited vibrational states are ≈127, 9.5, and 1.5 for HC5N, HC7N, and HC9N, respectively. We find that these lowest-lying vibrational states are most probably populated via infrared pumping to vibrationally excited states lying at ≈600 cm-1. The lowest vibrationally excited states thus need to be taken into account to precisely determine absolute abundances and abundanceratios for long carbon chains. The abundance ratios N(HC5N)/N(HC7N) and N(HC7N)/N(HC9N) are 2.4 and 7.7 respectively.
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Affiliation(s)
- J. R. Pardo
- 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
| | - M. Agúndez
- 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
| | - J. P. Fonfría
- 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
- Dept. of Space, Earth and Environment, Chalmers University of Technology, Onsala Space Observatory, 439 92 Onsala, Sweden
| | - G. Quintana-Lacaci
- 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
| | - M. Guélin
- Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, F-38406, Saint Martin d’Hères, France
| | - J. Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
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