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Koelemay LA, Gold KR, Ziurys LM. Phosphorus-bearing molecules PO and PN at the edge of the Galaxy. Nature 2023; 623:292-295. [PMID: 37938703 PMCID: PMC10632128 DOI: 10.1038/s41586-023-06616-1] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 09/06/2023] [Indexed: 11/09/2023]
Abstract
Despite its importance in planet formation and biology1, phosphorus has been identified only in the inner 12 kpc of the Galaxy2-19. The study of this element has been hindered in part by unfavourable atomic transitions2,4,20. Phosphorus is thought to be created by neutron capture on 29Si and 30Si in massive stars20,21, and released into the interstellar medium by Type II supernova explosions2,22. However, models of galactic chemical evolution must arbitrarily increase the supernovae production23 to match observed abundances. Here we present the detection of gas-phase phosphorus in the Outer Galaxy through millimetre spectra of PO and PN. Rotational lines of these molecules were observed in the dense cloud WB89-621, located 22.6 kpc from the Galactic Centre24. The abundances of PO and PN in WB89-621 are comparable to values near the Solar System25. Supernovae are not present in the Outer Galaxy26, suggesting another source of phosphorus, such as 'Galactic Fountains', where supernova material is redistributed through the halo and circumgalactic medium27. However, fountain-enriched clouds are not found at such large distances. Any extragalactic source, such as the Magellanic Clouds, is unlikely to be metal rich28. Phosphorus instead may be produced by neutron-capture processes in lower mass asymptotic giant branch stars29 which are present in the Outer Galaxy. Asymptotic giant branch stars also produce carbon21, flattening the extrapolated metallicity gradient and accounting for the high abundances of C-containing molecules in WB89-621.
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Affiliation(s)
- L A Koelemay
- Department of Chemistry, University of Arizona, Tucson, AZ, USA
| | - K R Gold
- Department of Chemistry, University of Arizona, Tucson, AZ, USA
| | - L M Ziurys
- Department of Chemistry, University of Arizona, Tucson, AZ, USA.
- Department of Astronomy, and Steward Observatory, University of Arizona, Tucson, AZ, USA.
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2
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Burton MA, Sheridan PM, Ziurys LM. The millimeter-wave spectrum of the SiP radical (X 2Π i): Rotational perturbations and hyperfine structure. J Chem Phys 2022; 157:184307. [DOI: 10.1063/5.0118939] [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: 11/11/2022] Open
Abstract
The millimeter/submillimeter-wave spectrum of the SiP radical (X2Πi) has been recorded using direct absorption spectroscopy in the frequency range of 151–532 GHz. SiP was synthesized in an AC discharge from the reaction of SiH4 and gas-phase phosphorus, in argon carrier gas. Both spin–orbit ladders were observed. Fifteen rotational transitions were measured originating in the Ω = 3/2 ladder, and twelve in the Ω = 1/2 substate, each exhibiting lambda doubling and, at lower frequencies, hyperfine interactions from the phosphorus nuclear spin of I = 1/2. The lambda-doublets in the Ω = 1/2 levels appeared to be perturbed at higher J, with the f component deviating from the predicted pattern, likely due to interactions with the nearby excited A2Σ+ electronic state, where ΔEΠ-Σ ∼ 430 cm−1. The data were analyzed using a Hund’s case a β Hamiltonian and rotational, spin–orbit, lambda-doubling, and hyperfine parameters were determined. A 2Π/2Σ deperturbation analysis was also performed, considering spin–orbit, spin-electronic, and L-uncoupling interactions. Although SiP is clearly not a hydride, the deperturbed parameters derived suggest that the pure precession hypothesis may be useful in assessing the 2Π/2Σ interaction. Interpretation of the Fermi contact term, b F, the spin-dipolar constant, c, and the nuclear spin-orbital parameter, a, indicates that the orbital of the unpaired electron is chiefly p π in character. The bond length in the v = 0 level was found to be r0 = 2.076 Å, suggestive of a double bond between the silicon and phosphorus atoms.
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Affiliation(s)
- M. A. Burton
- Department of Chemistry and Biochemistry, University of Arizona, 1305 E 4th Street, Tucson, Arizona 85719, USA
| | - P. M. Sheridan
- Department of Chemistry and Biochemistry, Canisius College, 2001 Main St., Buffalo, New York 14208, USA
| | - L. M. Ziurys
- Department of Chemistry and Biochemistry, University of Arizona, 1305 E 4th Street, Tucson, Arizona 85719, USA
- Department of Astronomy, Steward Observatory, University of Arizona, 944 N Cherry Ave., Tucson, Arizona 85718, USA
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Burton MA, Cheng Q, Halfen DT, Lane JH, DeYonker NJ, Ziurys LM. The structure of ScC 2 (X̃ 2A 1): A combined Fourier transform microwave/millimeter-wave spectroscopic and computational study. J Chem Phys 2020; 153:034304. [PMID: 32716169 DOI: 10.1063/5.0008746] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Pure rotational spectra of Sc13C2 (X̃2A1) and Sc12C13C (X̃2A') have been measured using Fourier transform microwave/millimeter-wave methods. These molecules were synthesized in a DC discharge from the reaction of scandium vapor, produced via laser ablation, with 13CH4 or 13CH4/12CH4, diluted in argon. The NKa,Kc = 10,1 → 00,0, 20,2 → 10,1, 30,3 → 20,2, and 40,4 → 30,3 transitions in the frequency range of 14 GHz-61 GHz were observed for both species, each exhibiting hyperfine splittings due to the nuclear spins of 13C (I = 1/2) and/or Sc (I = 7/2). These data have been analyzed with an asymmetric top Hamiltonian, and rotational, spin-rotation, and hyperfine parameters have been determined for Sc13C2 and Sc12C13C. In addition, a quartic force field was calculated for ScC2 and its isotopologues using a highly accurate coupled cluster-based composite method, incorporating complete basis set extrapolation, scalar relativistic corrections, outer core and inner core electron correlation, and higher-order valence correlation effects. The agreement between experimental and computed rotational constants, including the effective constant (B + C), is ∼0.5% for all three isotopologues. This remarkable agreement suggests promise in predicting rotational spectra of new transition metal-carbon bearing molecules. In combination with previous work on Sc12C2, an accurate structure for ScC2 has been established using combined experimental (B, C) and theoretical (A) rotational constants. The radical is cyclic (or T-shaped) with r(Sc-C) = 2.048(2) Å, r(C-C) = 1.272(2) Å, and ∠(C-Sc-C) = 36.2(1)°. The experimental and theoretical results also suggest that ScC2 contains a C2 - moiety and is largely ionic.
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Affiliation(s)
- M A Burton
- Department of Chemistry and Biochemistry, Department of Astronomy, Steward Observatory, University of Arizona, 1305 E. 4th Street, Tucson, Arizona 85719, USA
| | - Q Cheng
- Department of Chemistry, University of Memphis, Memphis, Tennessee 38152, USA
| | - D T Halfen
- Department of Chemistry and Biochemistry, Department of Astronomy, Steward Observatory, University of Arizona, 1305 E. 4th Street, Tucson, Arizona 85719, USA
| | - J H Lane
- Department of Chemistry and Biochemistry, Department of Astronomy, Steward Observatory, University of Arizona, 1305 E. 4th Street, Tucson, Arizona 85719, USA
| | - N J DeYonker
- Department of Chemistry, University of Memphis, Memphis, Tennessee 38152, USA
| | - L M Ziurys
- Department of Chemistry and Biochemistry, Department of Astronomy, Steward Observatory, University of Arizona, 1305 E. 4th Street, Tucson, Arizona 85719, USA
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Herman TJ, Keogh JP, Ziurys LM. Millimeter/sub-mm spectroscopy of the CrBr radical in the high spin X 6Σ + state. J Chem Phys 2019; 151:194301. [DOI: 10.1063/1.5125013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- T. J. Herman
- Department of Chemistry and Biochemistry, Department of Astronomy, and Steward Observatory, University of Arizona, 1305 E. 4th Street, Tucson, Arizona 85719, USA
| | - J. P. Keogh
- Department of Chemistry and Biochemistry, Department of Astronomy, and Steward Observatory, University of Arizona, 1305 E. 4th Street, Tucson, Arizona 85719, USA
| | - L. M. Ziurys
- Department of Chemistry and Biochemistry, Department of Astronomy, and Steward Observatory, University of Arizona, 1305 E. 4th Street, Tucson, Arizona 85719, USA
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Abstract
The pure rotational spectrum of ZnBr (X2Σ+) has been recorded in the frequency range 259-310 GHz using millimeter-wave direct absorption techniques. This study is the first quantitative spectroscopic investigation of this free radical. ZnBr was synthesized in a DC discharge by the reaction of zinc vapor in argon with one of three reagents: BrCH3, Br2CH2, or Br2. Eight rotational transitions were measured for six isotopologues (64Zn79Br, 64Zn81Br, 66Zn79Br, 66Zn81Br, 68Zn79Br, and 68Zn81Br), all of which exhibited spin-rotation interactions. Furthermore, transitions originating in the v = 1 through 3 excited vibrational states were obtained for certain isotopologues. Five rotational transitions were also recorded for 67Zn79Br, in which hyperfine splittings were observed arising from the 67Zn nucleus (I = 5/2). The spectra were analyzed using a Hund's case (bβJ) Hamiltonian, and rotational, spin-rotation, and 67Zn magnetic hyperfine constants were determined. Equilibrium parameters were also derived for the 64Zn79Br, 64Zn81Br, 66Zn79Br, and 66Zn81Br isotopologues, including the vibrational constant, ωe = 286 cm-1. The equilibrium bond length was derived to be re = 2.268 48(90) Å. Analysis of the 67Zn hyperfine parameters suggest a decrease in ionic character in ZnBr from the other known zinc halides, ZnF and ZnCl.
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Affiliation(s)
- M A Burton
- Department of Chemistry and Biochemistry, Department of Astronomy, and Steward Observatory, University of Arizona, 1305 E. 4th Street, Tucson, Arizona 85719, USA
| | - L M Ziurys
- Department of Chemistry and Biochemistry, Department of Astronomy, and Steward Observatory, University of Arizona, 1305 E. 4th Street, Tucson, Arizona 85719, USA
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Schmidt DR, Woolf NJ, Zega TJ, Ziurys LM. Extreme 13C, 15N and 17O isotopic enrichment in the young planetary nebula K4-47. Nature 2018; 564:378-381. [PMID: 30568193 DOI: 10.1038/s41586-018-0763-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 10/31/2018] [Indexed: 11/09/2022]
Abstract
Carbon, nitrogen and oxygen are the three most abundant elements in the Galaxy after hydrogen and helium. Whereas hydrogen and helium were created in the Big Bang, carbon, nitrogen and oxygen arise from nucleosynthesis in stars. Of particular interest1,2 are the isotopic ratios 12C/13C, 14N/15N and 16O/17O because they are effective tracers of nucleosynthesis and help to benchmark the chemical processes that occurred in primitive interstellar material as it evolved into our Solar System3. However, the origins of the rare isotopes 15N and 17O remain uncertain, although novae and very massive stars that explode as supernovae are postulated4-6 to be the main sources of 15N. Here we report millimetre-wavelength observations of the young bipolar planetary nebula K4-47 that indicate another possible source for these isotopes. We identify various carbon-bearing molecules in K4-47 that show that this object is carbon-rich, and find unusually high enrichment in rare carbon (13C), oxygen (17O) and nitrogen (15N) isotopes: 12C/13C = 2.2 ± 0.8, 16O/17O = 21.4 ± 10.3 and 14N/15N = 13.6 ± 6.5 (uncertainties are three standard deviations); for comparison, the corresponding solar ratios7 are 89.4 ± 0.2, 2,632 ± 7 and 435 ± 57. One possible interpretation of these results is that K4-47 arose from a J-type asymptotic giant branch star that underwent a helium-shell flash (an explosive nucleosynthetic event that converts large quantities of helium to carbon and other elements), enriching the resulting planetary nebula in 15N and 17O and creating its bipolar geometry. Other possible explanations are that K4-47 is a binary system or that it resulted from a white dwarf merger, as has been suggested for object CK Vul8. These results suggest that nucleosynthesis of carbon, nitrogen and oxygen is not well understood and that the classification of certain stardust grains must be reconsidered.
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Affiliation(s)
- D R Schmidt
- Department of Astronomy, Steward Observatory, University of Arizona, Tucson, AZ, USA
| | - N J Woolf
- Department of Astronomy, Steward Observatory, University of Arizona, Tucson, AZ, USA
| | - T J Zega
- Department of Planetary Science, Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - L M Ziurys
- Department of Astronomy, Steward Observatory, University of Arizona, Tucson, AZ, USA. .,Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA. .,Arizona Radio Observatory, Steward Observatory, University of Arizona, Tucson, AZ, USA.
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Abstract
The pure rotational spectrum of the AlC2 radical (X[combining tilde]2A1) has been measured using Fourier transform microwave/millimeter-wave (FTMmmW) techniques in the frequency range 21-65 GHz. This study is the first high-resolution spectroscopic investigation of this molecule. AlC2 was created in a supersonic jet from the reaction of aluminum, generated by laser ablation, with a mixture of CH4 or HCCH, diluted in argon, in the presence of a DC discharge. Three transitions (NKa,Kc = 101 → 000, 202 → 101, and 303 → 202) were measured, each consisting of multiple fine/hyperfine components, resulting from the unpaired electron in the species and the aluminum-27 nuclear spin (I = 5/2). The data were analyzed using an asymmetric top Hamiltonian and rotational, fine structure, and hyperfine constants determined. These parameters agree well with those derived from previous theoretical calculations and optical spectra. An r0 structure of AlC2 was determined with r(Al-C) = 1.924 Å, r(C-C) = 1.260 Å, and θ(C-Al-C) = 38.2°. The Al-C bond was found to be significantly shorter than in other small, Al-bearing species. The Fermi contact term established in this work indicates that the unpaired electron in the valence orbital has considerable 3pza1 character, suggesting polarization towards the C2 moiety. A high degree of ionic character in the molecule is also evident from the quadrupole coupling constant. These results are consistent with a T-shaped geometry and an Al+C2- bonding scheme. AlC2 is a possible interstellar molecule that may be present in the circumstellar envelopes of carbon-rich AGB stars.
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Affiliation(s)
- D T Halfen
- Department of Chemistry and Biochemistry, Department of Astronomy, and Steward Observatory, University of Arizona, 1305 E. 4th Street, Tucson, AZ 85719, USA.
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Bucchino MP, Adande GR, Halfen DT, Ziurys LM. Examining transition metal hydrosulfides: The pure rotational spectrum of ZnSH (X̃ 2A'). J Chem Phys 2017; 147:154313. [PMID: 29055338 DOI: 10.1063/1.4999924] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The pure rotational spectrum of the ZnSH (X̃2A') radical has been measured using millimeter-wave direct absorption and Fourier transform microwave (FTMW) methods across the frequency range 18-468 GHz. This work is the first gas-phase detection of ZnSH by any spectroscopic technique. Spectra of the 66ZnSH, 68ZnSH, and 64ZnSD isotopologues were also recorded. In the mm-wave study, ZnSH was synthesized in a DC discharge by the reaction of zinc vapor, generated by a Broida-type oven, with H2S; for FTMW measurements, the radical was made in a supersonic jet expansion by the same reactants but utilizing a discharge-assisted laser ablation source. Between 7 and 9 rotational transitions were recorded for each isotopologue. Asymmetry components with Ka = 0 through 6 were typically measured in the mm-wave region, each split into spin-rotation doublets. In the FTMW spectra, hyperfine interactions were also resolved, arising from the hydrogen or deuterium nuclear spins of I = 1/2 or I = 1, respectively. The data were analyzed using an asymmetric top Hamiltonian, and rotational, spin-rotation, and magnetic hyperfine parameters were determined for ZnSH, as well as the quadrupole coupling constant for ZnSD. The observed spectra clearly indicate that ZnSH has a bent geometry. The rm(1) structure was determined to be rZn-S = 2.213(5) Å, rS-H = 1.351(3) Å, and θZn-S-H = 90.6(1)°, suggesting that the bonding occurs primarily through sulfur p orbitals, analogous to H2S. The hyperfine constants indicate that the unpaired electron in ZnSH primarily resides on the zinc nucleus.
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Affiliation(s)
- M P Bucchino
- Department of Chemistry and Biochemistry, Department of Astronomy, Arizona Radio Observatory, University of Arizona, Tucson, Arizona 85719, USA
| | - G R Adande
- Department of Chemistry and Biochemistry, Department of Astronomy, Arizona Radio Observatory, University of Arizona, Tucson, Arizona 85719, USA
| | - D T Halfen
- Department of Chemistry and Biochemistry, Department of Astronomy, Arizona Radio Observatory, University of Arizona, Tucson, Arizona 85719, USA
| | - L M Ziurys
- Department of Chemistry and Biochemistry, Department of Astronomy, Arizona Radio Observatory, University of Arizona, Tucson, Arizona 85719, USA
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Ziurys LM, Halfen DT, Geppert W, Aikawa Y. Following the Interstellar History of Carbon: From the Interiors of Stars to the Surfaces of Planets. Astrobiology 2016; 16:997-1012. [PMID: 28001448 DOI: 10.1089/ast.2016.1484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The chemical history of carbon is traced from its origin in stellar nucleosynthesis to its delivery to planet surfaces. The molecular carriers of this element are examined at each stage in the cycling of interstellar organic material and their eventual incorporation into solar system bodies. The connection between the various interstellar carbon reservoirs is also examined. Carbon has two stellar sources: supernova explosions and mass loss from evolved stars. In the latter case, the carbon is dredged up from the interior and then ejected into a circumstellar envelope, where a rich and unusual C-based chemistry occurs. This molecular material is eventually released into the general interstellar medium through planetary nebulae. It is first incorporated into diffuse clouds, where carbon is found in polyatomic molecules such as H2CO, HCN, HNC, c-C3H2, and even C60+. These objects then collapse into dense clouds, the sites of star and planet formation. Such clouds foster an active organic chemistry, producing compounds with a wide range of functional groups with both gas-phase and surface mechanisms. As stars and planets form, the chemical composition is altered by increasing stellar radiation, as well as possibly by reactions in the presolar nebula. Some molecular, carbon-rich material remains pristine, however, encapsulated in comets, meteorites, and interplanetary dust particles, and is delivered to planet surfaces. Key Words: Carbon isotopes-Prebiotic evolution-Interstellar molecules-Comets-Meteorites. Astrobiology 16, 997-1012.
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Affiliation(s)
- L M Ziurys
- 1 Department of Chemistry and Biochemistry, Department of Astronomy, and Arizona Radio Observatory, University of Arizona , Tucson, Arizona, USA
| | - D T Halfen
- 1 Department of Chemistry and Biochemistry, Department of Astronomy, and Arizona Radio Observatory, University of Arizona , Tucson, Arizona, USA
| | - W Geppert
- 2 Physics Department, Stockholm University , Stockholm, Sweden
| | - Y Aikawa
- 3 Center for Computational Sciences, University of Tsukuba , Tsukuba, Japan
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Affiliation(s)
- J. Min
- Department of Chemistry and Biochemistry, Department of Astronomy, Steward Observatory, 933 North Cherry Avenue, University of Arizona, Tucson, Arizona 85721, USA
| | - L. M. Ziurys
- Department of Chemistry and Biochemistry, Department of Astronomy, Steward Observatory, 933 North Cherry Avenue, University of Arizona, Tucson, Arizona 85721, USA
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Halfen DT, Ziurys LM. SUBMILLIMETER/THz ROTATIONAL SPECTROSCOPY OF SH+(${X}^{3}{{\rm{\Sigma }}}^{-}$): THE COMPLETEN= $1\leftarrow 0$ TRANSITION. ACTA ACUST UNITED AC 2015. [DOI: 10.1088/0004-637x/814/2/119] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Halfen DT, Ilyushin VV, Ziurys LM. INTERSTELLAR DETECTION OF METHYL ISOCYANATE CH
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NCO IN Sgr B2(N): A LINK FROM MOLECULAR CLOUDS TO COMETS. ACTA ACUST UNITED AC 2015. [DOI: 10.1088/2041-8205/812/1/l5] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Ziurys LM, Adande GR, Edwards JL, Schmidt DR, Halfen DT, Woolf NJ. Prebiotic chemical evolution in the astrophysical context. ORIGINS LIFE EVOL B 2015; 45:275-88. [PMID: 25894971 DOI: 10.1007/s11084-015-9431-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 01/18/2015] [Indexed: 11/24/2022]
Abstract
An ever increasing amount of molecular material is being discovered in the interstellar medium, associated with the birth and death of stars and planetary systems. Radio and millimeter-wave astronomical observations, made possible by high-resolution laboratory spectroscopy, uniquely trace the history of gas-phase molecules with biogenic elements. Using a combination of both disciplines, the full extent of the cycling of molecular matter, from circumstellar ejecta of dying stars - objects which expel large amounts of carbon - to nascent solar systems, has been investigated. Such stellar ejecta have been found to exhibit a rich and varied chemical content. Observations demonstrate that this molecular material is passed onto planetary nebulae, the final phase of stellar evolution. Here the star sheds almost its entire original mass, becoming an ultraviolet-emitting white dwarf. Molecules such as H2CO, HCN, HCO(+), and CCH are present in significant concentrations across the entire age span of such nebulae. These data suggest that gas-phase polyatomic, carbon-containing molecules survive the planetary nebula phase and subsequently are transported into the interstellar medium, seeding the chemistry of diffuse and then dense clouds. The extent of the chemical complexity in dense clouds is unknown, hindered by the high spectral line density. Organic species such as acetamide and methyl amine are present in such objects, and NH2CHO has a wide Galactic distribution. However, organophosphorus compounds have not yet been detected in dense clouds. Based on carbon and nitrogen isotope ratios, molecular material from the ISM appears to become incorporated into solar system planetesimals. It is therefore likely that interstellar synthesis influences prebiotic chemistry on planet surfaces.
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Affiliation(s)
- L M Ziurys
- Department of Chemistry, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ, 85721-0065, USA,
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14
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Bucchino MP, Sheridan PM, Young JP, Binns MKL, Ewing DW, Ziurys LM. Trends in alkali metal hydrosulfides: a combined Fourier transform microwave/millimeter-wave spectroscopic study of KSH (X1A'). J Chem Phys 2013; 139:214307. [PMID: 24320380 DOI: 10.1063/1.4834656] [Citation(s) in RCA: 5] [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: 12/23/2022] Open
Abstract
The pure rotational spectrum of KSH (X(1)A') has been measured using millimeter-wave direct absorption and Fourier transform microwave (FTMW) techniques. This work is the first gas-phase experimental study of this molecule and includes spectroscopy of KSD as well. In the millimeter-wave system, KSH was synthesized in a DC discharge from a mixture of potassium vapor, H2S, and argon; a discharge-assisted laser ablation source, coupled with a supersonic jet expansion, was used to create the species in the FTMW instrument. Five and three rotational transitions in the range 3-57 GHz were recorded with the FTMW experiment for KSH and KSD, respectively, in the K(a) = 0 component; in these data, potassium quadrupole hyperfine structure was observed. Five to six transitions with K(a) = 0-5 were measured in the mm-wave region (260-300 GHz) for the two species. The presence of multiple asymmetry components in the mm-wave spectra indicates that KSH has a bent geometry, in analogy to other alkali hydrosulfides. The data were analyzed with an S-reduced asymmetric top Hamiltonian, and rotational, centrifugal distortion, and potassium electric quadrupole coupling constants were determined for both isotopolgues. The r0 geometry for KSH was calculated to be r(S-H) = 1.357(1) Å, r(K-S) = 2.806(1) Å, and θ(M-S-H) (°) = 95.0 (1). FTMW measurements were also carried out on LiSH and NaSH; metal electric quadrupole coupling constants were determined for comparison with KSH. In addition, ab initio computations of the structures and vibrational frequencies at the CCSD(T)/6-311++G(3df,2pd) and CCSD(T)/aug-cc-pVTZ levels of theory were performed for LiSH, NaSH, and KSH. Overall, experimental and computational data suggest that the metal-ligand bonding in KSH is a combination of electrostatic and covalent forces.
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Affiliation(s)
- M P Bucchino
- Department of Chemistry and Biochemistry, Department of Astronomy, and Steward Observatory, University of Arizona, Tucson, Arizona 85721, USA
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Halfen DT, Sun M, Harris B, Ziurys LM. The microwave and millimeter spectrum of ZnCCH (X̃2Σ+): A new zinc-containing free radical. J Chem Phys 2012; 136:244310. [DOI: 10.1063/1.4729943] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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Affiliation(s)
- D T Halfen
- Department of Chemistry, Arizona Radio Observatory and Steward Observatory, University of Arizona, Tucson AZ 85721, USA
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Savin DW, Brickhouse NS, Cowan JJ, Drake RP, Federman SR, Ferland GJ, Frank A, Gudipati MS, Haxton WC, Herbst E, Profumo S, Salama F, Ziurys LM, Zweibel EG. The impact of recent advances in laboratory astrophysics on our understanding of the cosmos. Rep Prog Phys 2012; 75:036901. [PMID: 22790424 DOI: 10.1088/0034-4885/75/3/036901] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
An emerging theme in modern astrophysics is the connection between astronomical observations and the underlying physical phenomena that drive our cosmos. Both the mechanisms responsible for the observed astrophysical phenomena and the tools used to probe such phenomena-the radiation and particle spectra we observe-have their roots in atomic, molecular, condensed matter, plasma, nuclear and particle physics. Chemistry is implicitly included in both molecular and condensed matter physics. This connection is the theme of the present report, which provides a broad, though non-exhaustive, overview of progress in our understanding of the cosmos resulting from recent theoretical and experimental advances in what is commonly called laboratory astrophysics. This work, carried out by a diverse community of laboratory astrophysicists, is increasingly important as astrophysics transitions into an era of precise measurement and high fidelity modeling.
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Affiliation(s)
- D W Savin
- Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027, USA
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Flory MA, Ziurys LM. Millimeter-wave rotational spectroscopy of FeCN (X 4Δi) and FeNC (X 6Δi): Determining the lowest energy isomer. J Chem Phys 2011; 135:184303. [PMID: 22088061 DOI: 10.1063/1.3653809] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- M A Flory
- Department of Chemistry and Department of Astronomy, Steward Observatory, University of Arizona, 933 N. Cherry Ave., Tucson, Arizona 85721, USA
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Halfen DT, Clouthier DJ, Ziurys LM, Lattanzi V, McCarthy MC, Thaddeus P, Thorwirth S. The pure rotational spectrum of HPS (X̃1A′): Chemical bonding in second-row elements. J Chem Phys 2011; 134:134302. [PMID: 21476750 DOI: 10.1063/1.3562374] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- D T Halfen
- Department of Chemistry, Arizona Radio Observatory, and Steward Observatory University of Arizona, Tucson, Arizona 85721, USA
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Sun M, Halfen DT, Min J, Harris B, Clouthier DJ, Ziurys LM. The rotational spectrum of CuCCH(X̃ Σ1+): A Fourier transform microwave discharge assisted laser ablation spectroscopy and millimeter/submillimeter study. J Chem Phys 2010; 133:174301. [DOI: 10.1063/1.3493690] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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Sun M, Clouthier DJ, Ziurys LM. The Fourier transform microwave spectrum of the arsenic dicarbide radical (CCAs: X̃Π1∕22) and its C13 isotopologues. J Chem Phys 2009; 131:224317. [DOI: 10.1063/1.3267483] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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Affiliation(s)
- D. T. Halfen
- Department of Chemistry, Department of Astronomy, Arizona Radio Observatory, and Steward Observatory, University of Arizona, 933 N. Cherry Avenue, Tucson, Arizona 85721
| | - L. M. Ziurys
- Department of Chemistry, Department of Astronomy, Arizona Radio Observatory, and Steward Observatory, University of Arizona, 933 N. Cherry Avenue, Tucson, Arizona 85721
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Halfen DT, Ziurys LM, Brown JM. Fine structure and hyperfine perturbations in the pure rotational spectrum of the VCl radical in its X Δ5r state. J Chem Phys 2009; 130:164301. [DOI: 10.1063/1.3108538] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Halfen DT, Sun M, Clouthier DJ, Ziurys LM. The rotational spectrum of the CCP (XΠr2) radical and its C13 isotopologues at microwave, millimeter, and submillimeter wavelengths. J Chem Phys 2009; 130:014305. [PMID: 19140613 DOI: 10.1063/1.3043367] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- D T Halfen
- Department of Chemistry, Arizona Radio Observatory, University of Arizona, Tucson, Arizona 85721, USA.
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Harrison JJ, Brown JM, Flory MA, Sheridan PM, McLamarrah SK, Ziurys LM. The rotational spectrum of CoF in all three spin-orbit components of the XΦi3 state. J Chem Phys 2007; 127:194308. [DOI: 10.1063/1.2789427] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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Ziurys LM, Milam SN, Apponi AJ, Woolf NJ. Chemical complexity in the winds of the oxygen-rich supergiant star VY Canis Majoris. Nature 2007; 447:1094-7. [PMID: 17597755 DOI: 10.1038/nature05905] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Accepted: 05/04/2007] [Indexed: 11/09/2022]
Abstract
The interstellar medium is enriched primarily by matter ejected from old, evolved stars. The outflows from these stars create spherical envelopes, which foster gas-phase chemistry. The chemical complexity in circumstellar shells was originally thought to be dominated by the elemental carbon to oxygen ratio. Observations have suggested that envelopes with more carbon than oxygen have a significantly greater abundance of molecules than their oxygen-rich analogues. Here we report observations of molecules in the oxygen-rich shell of the red supergiant star VY Canis Majoris (VY CMa). A variety of unexpected chemical compounds have been identified, including NaCl, PN, HNC and HCO+. From the spectral line profiles, the molecules can be distinguished as arising from three distinct kinematic regions: a spherical outflow, a tightly collimated, blue-shifted expansion, and a directed, red-shifted flow. Certain species (SiO, PN and NaCl) exclusively trace the spherical flow, whereas HNC and sulphur-bearing molecules (amongst others) are selectively created in the two expansions, perhaps arising from shock waves. CO, HCN, CS and HCO+ exist in all three components. Despite the oxygen-rich environment, HCN seems to be as abundant as CO. These results suggest that oxygen-rich shells may be as chemically diverse as their carbon counterparts.
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Affiliation(s)
- L M Ziurys
- NASA Astrobiology Institute, Tucson, Arizona 85721, USA.
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Abstract
Prebiotic possibilities for the synthesis of interstellar ribose through a protic variant of the formose reaction under gas-phase conditions were studied in the absence of any known catalyst. The ion-molecule reaction products, diose and triose, were sought by mass spectrometry, and relevant masses were observed. Ab initio calculations were used to evaluate protic formose mechanism possibilities. A bilateral theoretical and experimental effort yielded a physical model for glycoaldehyde generation whereby a hydronium cation can mediate formaldehyde dimerization followed by covalent bond formation leading to diose and water. These results advance the possibility that ion-molecule reactions between formaldehyde (CH(2)O) and H(3)O(+) lead to formose reaction products and inform us about potential sugar formation processes in interstellar space.
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Affiliation(s)
- Abraham F Jalbout
- Instituto de Quimica, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Mexico D.F.
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Abstract
The pure rotational spectrum of the ZnF radical has been recorded in the range of 176-527 GHz using millimeter/submillimeter direct absorption techniques. This study is the first gas-phase spectroscopic investigation of this species. Between 5 and 11 transitions were measured for each of five isotopologues of this radical (64ZnF, 66ZnF, 67ZnF, 68ZnF, and 70ZnF) in the ground and several excited vibrational (v=1, 2, and 3) states. Each transition consists of spin-rotation doublets with a splitting of approximately 150 MHz, indicating that the electronic ground state of ZnF is 2Sigma+, as predicted by theory. Fluorine hyperfine splitting was observed in three isotopologues (64ZnF, 66ZnF, and 67ZnF), and hyperfine structure from the zinc-67 nucleus (I=52) was additionally resolved in 67ZnF. Rotational, fine structure, and 19F and 67Zn hyperfine constants were determined for ZnF, as well as equilibrium parameters. The bond length of the main isotopologue 64ZnF was calculated to be re=1.7677 A. Evaluation of the hyperfine constants indicates that the sigma orbital containing the unpaired electron is approximately 80% 4s(Zn) in character with approximately 10% contributions from each of the 2p(F) and 4p(Zn) orbitals. These results imply that ZnF is somewhat less ionic than CaF, as suggested by theory.
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Affiliation(s)
- M A Flory
- Department of Chemistry, Steward Observatory, University of Arizona, Tucson, Arizona 85721, USA
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Abstract
The pure rotational spectrum of CoS, the cobalt sulfide radical, has been measured using direct absorption techniques in the frequency range of 180-540 GHz. This study is the first spectroscopic investigation of any kind of this molecule. CoS was created by reacting cobalt vapor with H2S. Four spin components were identified in the spectra of this species, one of which exhibited lambda doubling, identifying the ground state as 4Deltai. Transitions arising from the lowest spin component of the less abundant Co 35S isotopomer have also been detected, as well as from v=1 and v=2 of the main species. The spectra were readily identified because each spin component exhibited an octet pattern arising from the 59Co spin of I=72. The data were fit using Hund's case (a) Hamiltonian, and rotational, fine-structure, hyperfine, and lambda-doubling constants were determined. The hyperfine parameters support a delta3pi2 electron configuration and are consistent with some orbital overlap between the metal and sulfur atoms. From the rotational constant, the bond length of CoS was calculated to be r0=1.977 985 06(10) A. This bond length is significantly shorter than that of MnS or FeS, in contrast to the bond distances found in the oxide analogs which are all similar in value. These results indicate that the 3d metal sulfides differ somewhat from their oxide counterparts, probably due to the availability of sulfur p orbitals for bonding.
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Affiliation(s)
- M A Flory
- Department of Chemistry, Department of Astronomy, and Steward Observatory, University of Arizona, Tucson, Arizona 85721, USA
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Halfen DT, Ziurys LM. Molecules in high spin states III: The millimeter/submillimeter-wave spectrum of the MnCl radical (X 7Σ+). J Chem Phys 2005; 122:54309. [PMID: 15740324 DOI: 10.1063/1.1824036] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The pure rotational spectrum of the MnCl radical (X (7)Sigma(+)) has been recorded in the range 141-535 GHz using millimeter-submillimeter direct absorption spectroscopy. This work is the first time the molecule has been studied with rotational resolution in its ground electronic state. MnCl was synthesized by the reaction of manganese vapor, produced in a Broida-type oven, with Cl(2). Transitions of both chlorine isotopomers were measured, as well as lines originating in several vibrationally excited states. The presence of several spin components and manganese hyperfine interactions resulted in quite complex spectra, consisting of multiple blended features. Because 42 rotational transitions were measured for Mn(35)Cl over a wide range of frequencies with high signal-to-noise, a very accurate set of rotational, fine structure, and hyperfine constants could be determined with the aid of spectral simulations. Spectroscopic constants were also determined for Mn(37)Cl and several vibrationally excited states. The values of the spin-rotation and spin-spin parameters were found to be relatively small (gamma=11.2658 MHz and lambda=1113.10 MHz for Mn(35)Cl); in the case of lambda, excited electronic states contributing to the second-order spin-orbit interaction may be canceling each other. The Fermi contact hyperfine term was found to be large in manganese chloride with b(F)(Mn(35)Cl)=397.71 MHz, a result of the manganese 4s character mixing into the 12sigma orbital. This orbital is spsigma hybridized, and contains some Mn 4psigma character, as well. Hence, it also contributes to the dipolar constant c, which is small and positive for this radical (c=32.35 MHz for Mn(35)Cl). The hyperfine parameters in MnCl are similar to those of MnH and MnF, suggesting that the bonding in these three molecules is comparable.
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Affiliation(s)
- D T Halfen
- Department of Chemistry, Department of Astronomy, Arizona Radio Observatory, and Steward Observatory, University of Arizona, Tucson, AZ 85721, USA
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Sheridan PM, Flory MA, Ziurys LM. Characterizing the later 3d cyanides: The submillimeter spectrum of CoCN(X [sup 3]Φ[sub i]). J Chem Phys 2004; 121:8360-8. [PMID: 15511156 DOI: 10.1063/1.1791091] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The pure rotational spectrum of the CoCN radical has been recorded in the frequency range 350-500 GHz using direct absorption techniques. This study is the first spectroscopic observation of this molecule by any experimental technique. Spectra of Co (13)CN have been measured as well. These data indicate that this species is linear in its ground electronic state and has the cyanide, as opposed to the isocyanide, geometry. The ground state term has been assigned as (3)Phi(i), based on the measurement of three spin components (Omega=4, 3, and 2) and in analogy to other isovalent cobalt-bearing species. Hyperfine splittings resulting from the (59)Co nuclear spin of I=7/2 were observed in every transition, each of which exhibited an octet pattern. For the lowest energy spin component, Omega=4, vibrational satellite features were also identified arising from the first quantum of the Co-C (v(1)=1) stretch and the v(2)=1 and v(2)=2 quanta of the bending mode, which were split by Renner-Teller interactions. The ground state measurements of CoCN were analyzed with a case a(beta) Hamiltonian, establishing rotational, fine structure, and hyperfine parameters. The vibrational and Co (13)CN spectra for the Omega=4 component were fit as well. An r(0) structure was also calculated, providing estimates of the Co-C and C-N bond distances, based on the Omega=4 transitions. CoCN is the fourth molecule in the 3d transition metal series to exhibit the linear cyanide structure, along with the Zn, Cu, and Ni analogs. The preference for this geometry, as opposed to the isocyanide form, may indicate a greater degree of covalent bonding in these species.
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Affiliation(s)
- P M Sheridan
- Department of Chemistry, and Steward Observatory, University of Arizona, Tucson, AZ 85721, USA
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Flory MA, Halfen DT, Ziurys LM. Perturbations in the pure rotational spectrum of CoCl (X [sup 3]Φ[sub i]): A submillimeter study. J Chem Phys 2004; 121:8385-92. [PMID: 15511159 DOI: 10.1063/1.1795691] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The millimeter/submillimeter-wave spectrum of the CoCl radical (X (3)Phi(i)) has been recorded using direct absorption techniques in the frequency range 340-510 GHz. This work is the first pure rotational study of this molecule. The radical was created by the reaction of Cl(2) with cobalt vapor. Rotational transitions arising from the Omega=4, 3, and 2 spin-orbit components of Co(35)Cl have been measured, all of which exhibit hyperfine splittings due to the (59)Co nucleus (I=7/2). Transitions arising from the Co(37)Cl species were also recorded, as well as those originating in the v=1, 2, 3, and 4 vibrational states of both isotopomers. The spin-orbit pattern exhibited by the molecule is unusual, with the Omega=3 component significantly shifted relative to the other spin components. In addition, the regular octet hyperfine splittings become distorted above a certain J value for the Omega=3 transitions only. These effects suggest that the molecule is highly perturbed in its ground state, most likely a result of second-order spin-orbit mixing with a nearby isoconfigurational (1)Phi(3) state. The complete data set for Co(35)Cl and Co(37)Cl were fit successfully with a case (a) Hamiltonian but required a large negative spin-spin constant of lambda=-7196 GHz and higher order centrifugal distortion corrections to the rotational, spin-orbit, spin-spin, and hyperfine terms. The value of the spin-spin constant suggests that the Omega=3 component is shifted to higher energy and lies near the Omega=2 sublevel. The hyperfine parameters are consistent with a delta(3)pi(3) electron configuration and indicate that CoCl is more covalent than CoF.
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Affiliation(s)
- M A Flory
- Department of Chemistry, and Steward Observatory, University of Arizona, Tucson, AZ 85721, USA
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Sheridan PM, McLamarrah SK, Ziurys LM. The pure rotational spectrum of TiF (X 4Φr): 3d transition metal fluorides revisited. J Chem Phys 2003. [DOI: 10.1063/1.1615753] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Brewster MA, Ziurys LM. Rotational spectroscopy of 3d transition-metal cyanides: Millimeter-wave studies of ZnCN (X 2Σ+). J Chem Phys 2002. [DOI: 10.1063/1.1498466] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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Thompsen JM, Brewster MA, Ziurys LM. Molecules in high spin states: The millimeter and submillimeter spectrum of the MnS radical (X 6Σ+). J Chem Phys 2002. [DOI: 10.1063/1.1476931] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Sheridan PM, Xin J, Ziurys LM, Beaton SA, Kermode SM, Brown JM. The pure rotational spectrum of NaC in its X 4Σ− state: Observation and interpretation. J Chem Phys 2002. [DOI: 10.1063/1.1457441] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Halfen DT, Apponi AJ, Thompsen JM, Ziurys LM. The pure rotational spectra of SrSH (X̃ 2A′) and SrS (X 1Σ+): Further studies in alkaline-earth bonding. J Chem Phys 2001. [DOI: 10.1063/1.1419060] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Irvine WM, Avery LW, Friberg P, Matthews HE, Ziurys LM. Newly detected molecules in dense interstellar clouds. Astrophys Lett Commun 2001; 26:167-80. [PMID: 11538461] [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] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
The last year or so has seen the identification of several new interstellar molecules, including C2S, C3S, C5H, C6H, and (probably) HC2CHO in the cold, dark cloud TMC-1; and the discovery of the first interstellar phosphorous-containing molecule, PN, in the Orion "plateau" source. Further interesting results include the observations of 13C3H2 and C3HD, and the first detection of HCOOH (formic acid) in a cold cloud.
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Affiliation(s)
- W M Irvine
- FCRAO, University of Massachusetts, Amherst 01003, USA
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Grotjahn DB, Sheridan PM, Al Jihad I, Ziurys LM. First synthesis and structural determination of a monomeric, unsolvated lithium amide, LiNH(2). J Am Chem Soc 2001; 123:5489-94. [PMID: 11389631 DOI: 10.1021/ja003422h] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [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
Alkali metal amides typically aggregate in solution and the solid phase, and even in the gas phase. In addition, even in the few known monomeric structures, the coordination number of the alkali metal is raised by binding of Lewis-basic solvent molecules, with concomitant changes in structure. In contrast, the simplest lithium amide LiNH(2) has never been made in a monomeric form, even though its structure has been theoretically predicted several times. Here, the first experimental structural data for a monomeric, unsolvated lithium amide are determined using a combination of gas-phase synthesis and millimeter/submillimeter-wave spectroscopy. All data point to a planar structure for LiNH(2). The r(o) structure of LiNH(2) has a Li-N distance of 1.736(3) A, an N-H distance of 1.022(3) A, and a H-N-H angle of 106.9(1) degrees. These results are compared with theoretical predictions for LiNH(2), and experimental data for oligomeric, solid-phase samples, which could not resolve the question of whether LiNH(2) is planar or not. In addition, comparisons are made with revised gas-phase and solid-phase data and calculated structures of NaNH(2).
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Affiliation(s)
- D B Grotjahn
- Department of Chemistry, San Diego State University, 5500 Campanile Drive, San Diego, California 92182-1030, USA
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Grotjahn DB, Pesch TC, Brewster MA, Ziurys LM. Synthesis of CH3K in the Gas Phase: Structural and Mechanistic Trends for Monomeric, Unsolvated CH3M and HCCM (M = Li, Na, K). J Am Chem Soc 2000. [DOI: 10.1021/ja993136+] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Apponi AJ, Anderson MA, Ziurys LM. High resolution spectroscopy of MgOH (X 2Σ+) in its V2 mode: Further evidence for quasilinearity. J Chem Phys 1999. [DOI: 10.1063/1.480455] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- A. J. Apponi
- Department of Chemistry, Department of Astronomy, and Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, Arizona 85721
| | - M. A. Anderson
- Department of Chemistry, Department of Astronomy, and Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, Arizona 85721
| | - L. M. Ziurys
- Department of Chemistry, Department of Astronomy, and Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, Arizona 85721
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Ziurys LM, Savage C, Brewster MA, Apponi AJ, Pesch TC, Wyckoff S. Cyanide Chemistry in Comet Hale-Bopp (C/1995 O1). Astrophys J 1999; 527:L67-L71. [PMID: 10567001 DOI: 10.1086/312388] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Observations of comet Hale-Bopp (C/1995 O1) have been carried out near perihelion (1997 March) at millimeter wavelengths using the NRAO 12 m telescope. The J=1-->0, 2-->1, and 3-->2 lines of HCN at 88, 177, and 265 GHz were measured in the comet as well as the J=3-->2 lines of H13CN, HC15N, and HNC. The N=2-->1 transition of CN near 226 GHz was also detected, and an upper limit was obtained for the J=2-->1 line of HCNH+. From the measurements, column densities and production rates have been estimated. A column density ratio of [HCN]/[HNC] = 7+/-1 was observed near perihelion, while it was found that [HCN]/[HCNH+] greater, similar 1. The production rates at perihelion for HCN and CN were estimated to be Q(HCN) approximately 1x1028 s-1 and Q(CN) approximately 2.6x1027 s-1, respectively, resulting in a ratio of [HCN]/[CN] approximately 3. Consequently, HCN is sufficiently abundant to be the parent molecule of CN in Hale-Bopp, and HCNH+ could be a source of HNC. Finally, carbon and nitrogen isotope ratios of 12C/13C = 109+/-22 and 14N/15N = 330+/-98 were obtained from HCN measurements, in agreement with previous values obtained from J=4-->3 data. Such ratios suggest that comet Hale-Bopp formed coevally with the solar system.
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Xin J, Ziurys LM. Structural studies of alkali methylidyne radicals: High resolution spectroscopy of NaCH and KCH (X̃3Σ−). J Chem Phys 1999. [DOI: 10.1063/1.478202] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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