1
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Broadley MW, Bekaert DV, Piani L, Füri E, Marty B. Origin of life-forming volatile elements in the inner Solar System. Nature 2022; 611:245-255. [DOI: 10.1038/s41586-022-05276-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 08/25/2022] [Indexed: 11/11/2022]
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2
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Jiang P, Lu L, Liu M, Gao H. Multi-channel photodissociation dynamics of 14N 2 in its b' 1Σ+u( ν = 20) state. Phys Chem Chem Phys 2022; 24:11544-11551. [PMID: 35506911 DOI: 10.1039/d2cp01148d] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
b' 1Σ+u(ν = 20) is the first vibronic state above the dissociation limit N(2D3/2,5/2) + N(2D3/2,5/2) of 14N2 that has been observed in the absorption spectrum. It provides a unique opportunity for studying the multi-channel photodissociation dynamics of 14N2, particularly the competition between the spin-forbidden and spin-allowed photodissociation channels. Here, photofragment excitation (PHOFEX) and (1VUV + 1'UV) photoionization spectra of 14N2 in the b' 1Σ+u(ν = 20) state and the time-slice velocity-map ion (TS-VMI) images at each individual rotational levels are collected by using a vacuum ultraviolet (VUV) pump-VUV probe scheme. It is found that the spin-forbidden channels N(4S) + N(2D3/2,5/2) and N(4S) + N(2P1/2,3/2) are competitive with the spin-allowed channel N(2D3/2,5/2) + N(2D3/2,5/2) at low rotational levels, while quickly become undetectable as the rotational quantum number J increases. At high rotational levels, only the spin-allowed channel N(2D3/2,5/2) + N(2D3/2,5/2) can be observed, supporting previous theoretical modeling. Channel-resolved partial predissociation rate constants (PPRCs) are calculated by combining branching ratios in this study and total predissociation rate constants (TPRCs) from previous absorption spectroscopic measurements. PPRCs for dissociation into channels N(4S) + N(2D3/2,5/2) and N(4S) + N(2P1/2,3/2) are almost independent of J, while those of N(2D3/2,5/2) + N(2D3/2,5/2) show complicated rotational dependence. Possible coupling schemes between b' 1Σ+u(ν = 20) and the high lying 1Πu and 3Πu states are analyzed, which provides deep insight into the multi-channel photodissociation dynamics of 14N2 in a high energy range.
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Affiliation(s)
- Pan Jiang
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China. .,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Liya Lu
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China. .,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Min Liu
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China. .,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hong Gao
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China. .,University of Chinese Academy of Sciences, Beijing 100049, China
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3
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Liu M, Jiang P, Cheng M, Gao H. Vacuum ultraviolet photoexcitation and photofragment spectroscopic studies of 14N 15N between 109000 and 117500 cm -1. J Chem Phys 2021; 155:234305. [PMID: 34937384 DOI: 10.1063/5.0072604] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this study, we employed a newly built time-slice velocity-map ion imaging setup, equipped with two tunable vacuum ultraviolet (VUV) laser sources, to obtain the first comprehensive high-resolution photoexcitation and photofragment excitation spectra of 14N15N in the VUV photon energy range 109 000-117 500 cm-1. The spectroscopic simulation program PGOPHER was used to analyze the rotationally resolved spectra. Band origins, rotational constants, and isotope shifts compared with those of 14N2 have been obtained for 31 electric-dipole-allowed vibrational states of 14N15N in the aforementioned energy range. These spectroscopic parameters are found to depend on the vibrational quantum number irregularly. Systematic perturbations of the rotational transition energies and predissociation rates within individual absorption bands have also been observed. These are proved to be caused by the strong homogeneous interactions between the valence b'1Σu + state and the Rydberg cn ' 1Σu + states, and between the valence b1Πu states and the Rydberg o3 1Πu states. Heterogeneous interactions between the Rydberg cn 1Πu states and cn ' 1Σu + states also play an important role.
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Affiliation(s)
- Min Liu
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Pan Jiang
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Min Cheng
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Hong Gao
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
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4
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Gao H. Molecular photodissociation in the vacuum ultraviolet region: implications for astrochemistry and planetary atmospheric chemistry. Mol Phys 2020. [DOI: 10.1080/00268976.2020.1861354] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Hong Gao
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing, People’s Republic of China
- University of Chinese Academy of Sciences, Beijing, People’s Republic of China
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5
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Vollmer C, Leitner J, Kepaptsoglou D, Ramasse QM, King AJ, Schofield PF, Bischoff A, Araki T, Hoppe P. A primordial 15N-depleted organic component detected within the carbonaceous chondrite Maribo. Sci Rep 2020; 10:20251. [PMID: 33219224 PMCID: PMC7679378 DOI: 10.1038/s41598-020-77190-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 11/06/2020] [Indexed: 11/09/2022] Open
Abstract
We report on the detection of primordial organic matter within the carbonaceous chondrite Maribo that is distinct from the majority of organics found in extraterrestrial samples. We have applied high-spatial resolution techniques to obtain C-N isotopic compositions, chemical, and structural information of this material. The organic matter is depleted in 15N relative to the terrestrial value at around δ15N ~ -200‰, close to compositions in the local interstellar medium. Morphological investigations by electron microscopy revealed that the material consists of µm- to sub-µm-sized diffuse particles dispersed within the meteorite matrix. Electron energy loss and synchrotron X-ray absorption near-edge structure spectroscopies show that the carbon functional chemistry is dominated by aromatic and C=O bonding environments similar to primordial organics from other carbonaceous chondrites. The nitrogen functional chemistry is characterized by C-N double and triple bonding environments distinct from what is usually found in 15N-enriched organics from aqueously altered carbonaceous chondrites. Our investigations demonstrate that Maribo represents one of the least altered CM chondrite breccias found to date and contains primordial organic matter, probably originating in the interstellar medium.
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Affiliation(s)
- Christian Vollmer
- Institut für Mineralogie, Westfälische Wilhelms-Universität, Corrensstr. 24, 48149, Münster, Germany.
| | - Jan Leitner
- Particle Chemistry Department, Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, 55128, Mainz, Germany
| | - Demie Kepaptsoglou
- SuperSTEM Laboratory, Keckwick Lane, Daresbury, WA4 4AD, UK.,Jeol Nanocentre and Department of Physics, University of York, Heslington, YO10 5DD, UK
| | - Quentin M Ramasse
- SuperSTEM Laboratory, Keckwick Lane, Daresbury, WA4 4AD, UK.,School of Chemical and Process Engineering and School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
| | - Ashley J King
- Planetary Materials Group, Department of Earth Sciences, Natural History Museum, London, SW7 5BD, UK
| | - Paul F Schofield
- Planetary Materials Group, Department of Earth Sciences, Natural History Museum, London, SW7 5BD, UK
| | - Addi Bischoff
- Institut für Planetologie, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Str. 10, 48149, Münster, Germany
| | | | - Peter Hoppe
- Particle Chemistry Department, Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, 55128, Mainz, Germany
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6
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Lyons JR. An analytical formulation of isotope fractionation due to self-shielding. GEOCHIMICA ET COSMOCHIMICA ACTA 2020; 282:177-200. [PMID: 33005059 PMCID: PMC7526055 DOI: 10.1016/j.gca.2020.05.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Isotope fractionation due to photochemical self-shielding is believed to be responsible for the enrichment of inner solar system planetary materials in the rare isotopes of carbon, nitrogen, and oxygen relative to the Sun. Self-shielding may also contribute to sulfur isotope mass-independent fractionation in modern atmospheric sulfates, although its role in the early Earth atmosphere has not yet been convincingly established. Here, I present an analytical formulation of isotopic photodissociation rate coefficients that describe self-shielding isotope signatures for 3 and 4-isotope systems broadly representative of O and S isotopes. The analytic equations are derived for idealized molecular spectra, making an analytic formulation tractable. The idealized spectra characterize key features of actual isotopologue spectra, particularly for CO and SO2, but are applicable to many small molecules and their isotopologues. The analytic expressions are convenient for evaluating the magnitude of isotope effects without having to pursue involved numerical solutions. More importantly, the analytic expressions illustrate the origin of particular isotope signatures, such as the previously unexplained large mass-dependent fractionation associated with photodissociation of optically-thick SO2. The formulation presented here elucidates the origin of some of these important isotopic fractionation processes.
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Affiliation(s)
- J R Lyons
- School of Earth & Space Exploration, Arizona State University, PO Box 871404, Tempe, AZ 85287, United States
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7
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Jiang P, Chi X, Zhu Q, Cheng M, Gao H. Strong and selective isotope effect in the vacuum ultraviolet photodissociation branching ratios of carbon monoxide. Nat Commun 2019; 10:3175. [PMID: 31320624 PMCID: PMC6639306 DOI: 10.1038/s41467-019-11086-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 06/21/2019] [Indexed: 11/10/2022] Open
Abstract
Rare isotope (13C, 17O and 18O) substitutions can substantially change absorption line positions, oscillator strengths and photodissociation rates of carbon monoxide (CO) in the vacuum ultraviolet (VUV) region, which has been well accounted for in recent photochemical models for understanding the large isotopic fractionation effects that are apparent in carbon and oxygen in the solar system and molecular clouds. Here, we demonstrate a strong isotope effect associated with the VUV photodissociation of CO by measuring the branching ratios of 12C16O and 13C16O in the Rydberg 4p(2), 5p(0) and 5s(0) complex region. The measurements show that the quantum yields of electronically excited C atoms in the photodissociation of 13C16O are dramatically different from those of 12C16O, revealing strong isotope effect. This isotope effect strongly depends on specific quantum states of CO being excited, which implies that such effect must be considered in the photochemical models on a state by state basis.
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Affiliation(s)
- Pan Jiang
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaoping Chi
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Qihe Zhu
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Min Cheng
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
| | - Hong Gao
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
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8
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Dharampal PS, Carlson C, Currie CR, Steffan SA. Pollen-borne microbes shape bee fitness. Proc Biol Sci 2019; 286:20182894. [PMID: 31185869 PMCID: PMC6571465 DOI: 10.1098/rspb.2018.2894] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 05/17/2019] [Indexed: 01/15/2023] Open
Abstract
Teeming within pollen provisions are diverse communities of symbiotic microbes, which provide a variety of benefits to bees. Microbes themselves may represent a major dietary resource for developing bee larvae. Despite their apparent importance in sustaining bee health, evidence linking pollen-borne microbes to larval health is currently lacking. We examined the effects of microbe-deficient diets on the fitness of larval mason bees. In a series of diet manipulations, microbe-rich maternally collected pollen provisions were replaced with increasing fractions of sterilized, microbe-deficient pollen provisions before being fed to developing larvae. Convergent findings from amino acid and fatty acid trophic biomarker analyses revealed that larvae derived a substantial amount of nutrition from microbial prey and occupied a significantly higher trophic position than that of strict herbivores. Larvae feeding on increasingly sterile diets experienced significant adverse effects on growth rates, biomass and survivorship. When completely deprived of pollen-borne microbes, larvae consistently exhibited marked decline in fitness. We conclude that microbes associated with aged pollen provisions are central to bee health, not only as nutritional mutualists, but also as a major dietary component. In an era of global bee decline, the conservation of such bee-microbe interactions may represent an important facet of pollinator protection strategies.
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Affiliation(s)
| | - Caitlin Carlson
- Department of Bacteriology, University of Wisconsin, Madison, WI, USA
| | - Cameron R. Currie
- Department of Bacteriology, University of Wisconsin, Madison, WI, USA
| | - Shawn A. Steffan
- Department of Entomology, University of Wisconsin, Madison, WI, USA
- USDA-ARS, Vegetable Crops Research Unit, Madison, WI, USA
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9
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Thiemens MH, Lin M. Use of Isotope Effects To Understand the Present and Past of the Atmosphere and Climate and Track the Origin of Life. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201812322] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Mark H. Thiemens
- Department of Chemistry and BiochemistryUniversity of California San Diego La Jolla California 92093 USA
| | - Mang Lin
- Department of Chemistry and BiochemistryUniversity of California San Diego La Jolla California 92093 USA
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10
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Thiemens MH, Lin M. Use of Isotope Effects To Understand the Present and Past of the Atmosphere and Climate and Track the Origin of Life. Angew Chem Int Ed Engl 2019; 58:6826-6844. [PMID: 30633432 DOI: 10.1002/anie.201812322] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Indexed: 12/19/2022]
Abstract
Stable isotope ratio measurements have been used as a measure of a wide variety of processes, including solar system evolution, geological formational temperatures, tracking of atmospheric gas and aerosol chemical transformation, and is the only means by which past global temperatures may be determined over long time scales. Conventionally, isotope effects derive from differences of isotopically substituted molecules in isotope vibrational energy, bond strength, velocity, gravity, and evaporation/condensation. The variations in isotope ratio, such as 18 O/16 O (δ18 O) and 17 O/16 O (δ17 O) are dependent upon mass differences with δ17 O/δ18 O=0.5, due to the relative mass differences (1 amu vs. 2 amu). Relations that do not follow this are termed mass independent and are the focus of this Minireview. In chemical reactions such as ozone formation, a δ17 O/δ18 O=1 is observed. Physical chemical models capture most parameters but differ in basic approach and are reviewed. The mass independent effect is observed in atmospheric species and used to track their chemistry at the modern and ancient Earth, Mars, and the early solar system (meteorites).
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Affiliation(s)
- Mark H Thiemens
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, 92093, USA
| | - Mang Lin
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, 92093, USA
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11
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Carbon and oxygen isotopic fractionation in the products of low-temperature VUV photodissociation of carbon monoxide. Chem Phys 2018. [DOI: 10.1016/j.chemphys.2018.05.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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12
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Yeung LY, Li S, Kohl IE, Haslun JA, Ostrom NE, Hu H, Fischer TP, Schauble EA, Young ED. Extreme enrichment in atmospheric 15N 15N. SCIENCE ADVANCES 2017; 3:eaao6741. [PMID: 29159288 PMCID: PMC5693561 DOI: 10.1126/sciadv.aao6741] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 10/26/2017] [Indexed: 06/07/2023]
Abstract
Molecular nitrogen (N2) comprises three-quarters of Earth's atmosphere and significant portions of other planetary atmospheres. We report a 19 per mil (‰) excess of 15N15N in air relative to a random distribution of nitrogen isotopes, an enrichment that is 10 times larger than what isotopic equilibration in the atmosphere allows. Biological experiments show that the main sources and sinks of N2 yield much smaller proportions of 15N15N in N2. Electrical discharge experiments, however, establish 15N15N excesses of up to +23‰. We argue that 15N15N accumulates in the atmosphere because of gas-phase chemistry in the thermosphere (>100 km altitude) on time scales comparable to those of biological cycling. The atmospheric 15N15N excess therefore reflects a planetary-scale balance of biogeochemical and atmospheric nitrogen chemistry, one that may also exist on other planets.
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Affiliation(s)
- Laurence Y. Yeung
- Department of Earth, Environmental and Planetary Sciences, Rice University, Houston, TX 77005, USA
| | - Shuning Li
- Department of Earth, Environmental and Planetary Sciences, Rice University, Houston, TX 77005, USA
- Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, Los Angeles, CA 90089, USA
| | - Issaku E. Kohl
- Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, Los Angeles, CA 90089, USA
| | - Joshua A. Haslun
- Department of Integrative Biology and Department of Energy Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI 48824, USA
| | - Nathaniel E. Ostrom
- Department of Integrative Biology and Department of Energy Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI 48824, USA
| | - Huanting Hu
- Department of Earth, Environmental and Planetary Sciences, Rice University, Houston, TX 77005, USA
| | - Tobias P. Fischer
- Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM 87131, USA
| | - Edwin A. Schauble
- Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, Los Angeles, CA 90089, USA
| | - Edward D. Young
- Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, Los Angeles, CA 90089, USA
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13
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Chakraborty S, Jackson TL, Rude B, Ahmed M, Thiemens MH. Nitrogen isotopic fractionations in the low temperature (80 K) vacuum ultraviolet photodissociation of N2. J Chem Phys 2016. [DOI: 10.1063/1.4962447] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Affiliation(s)
- Subrata Chakraborty
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0356, USA
| | - Teresa L. Jackson
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0356, USA
| | - Bruce Rude
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA
| | - Musahid Ahmed
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA
| | - M. H. Thiemens
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0356, USA
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14
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Ajay J, Šmydke J, Remacle F, Levine RD. Probing in Space and Time the Nuclear Motion Driven by Nonequilibrium Electronic Dynamics in Ultrafast Pumped N2. J Phys Chem A 2016; 120:3335-42. [DOI: 10.1021/acs.jpca.6b00165] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- J. Ajay
- The
Fritz Haber Center for Molecular Dynamics and Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - J. Šmydke
- The
Fritz Haber Center for Molecular Dynamics and Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
- Department of Radiation and Chemical Physics, Institute of Physics, Academy of Sciences of the Czech Republic, 18221 Praha 8, Czech Republic
| | - F. Remacle
- The
Fritz Haber Center for Molecular Dynamics and Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
- Département
de Chimie, B6c, Université de Liège, B4000 Liège, Belgium
| | - R. D. Levine
- The
Fritz Haber Center for Molecular Dynamics and Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
- Crump
Institute for Molecular Imaging and Department of Molecular and Medical
Pharmacology, David Geffen School of Medicine and Department of Chemistry
and Biochemistry, University of California, Los Angeles, California 90095, United States
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15
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Fluid-induced organic synthesis in the solar nebula recorded in extraterrestrial dust from meteorites. Proc Natl Acad Sci U S A 2014; 111:15338-43. [PMID: 25288736 DOI: 10.1073/pnas.1408206111] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Isotopically anomalous carbonaceous grains in extraterrestrial samples represent the most pristine organics that were delivered to the early Earth. Here we report on gentle aberration-corrected scanning transmission electron microscopy investigations of eight (15)N-rich or D-rich organic grains within two carbonaceous Renazzo-type (CR) chondrites and two interplanetary dust particles (IDPs) originating from comets. Organic matter in the IDP samples is less aromatic than that in the CR chondrites, and its functional group chemistry is mainly characterized by C-O bonding and aliphatic C. Organic grains in CR chondrites are associated with carbonates and elemental Ca, which originate either from aqueous fluids or possibly an indigenous organic source. One distinct grain from the CR chondrite NWA 852 exhibits a rim structure only visible in chemical maps. The outer part is nanoglobular in shape, highly aromatic, and enriched in anomalous nitrogen. Functional group chemistry of the inner part is similar to spectra from IDP organic grains and less aromatic with nitrogen below the detection limit. The boundary between these two areas is very sharp. The direct association of both IDP-like organic matter with dominant C-O bonding environments and nanoglobular organics with dominant aromatic and C-N functionality within one unique grain provides for the first time to our knowledge strong evidence for organic synthesis in the early solar system activated by an anomalous nitrogen-containing parent body fluid.
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16
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Massive isotopic effect in vacuum UV photodissociation of N2 and implications for meteorite data. Proc Natl Acad Sci U S A 2014; 111:14704-9. [PMID: 25267643 DOI: 10.1073/pnas.1410440111] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Nitrogen isotopic distributions in the solar system extend across an enormous range, from -400‰, in the solar wind and Jovian atmosphere, to about 5,000‰ in organic matter in carbonaceous chondrites. Distributions such as these require complex processing of nitrogen reservoirs and extraordinary isotope effects. While theoretical models invoke ion-neutral exchange reactions outside the protoplanetary disk and photochemical self-shielding on the disk surface to explain the variations, there are no experiments to substantiate these models. Experimental results of N2 photolysis at vacuum UV wavelengths in the presence of hydrogen are presented here, which show a wide range of enriched δ(15)N values from 648‰ to 13,412‰ in product NH3, depending upon photodissociation wavelength. The measured enrichment range in photodissociation of N2, plausibly explains the range of δ(15)N in extraterrestrial materials. This study suggests the importance of photochemical processing of the nitrogen reservoirs within the solar nebula.
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17
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Randazzo JB, Croteau P, Kostko O, Ahmed M, Boering KA. Isotope effects and spectroscopic assignments in the non-dissociative photoionization spectrum of N2. J Chem Phys 2014; 140:194303. [DOI: 10.1063/1.4873717] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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18
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Muskatel B, Remacle F, Levine R. AttoPhotoChemistry. Probing ultrafast electron dynamics by the induced nuclear motion: The prompt and delayed predissociation of N2. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2014.03.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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19
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Vibronic origin of sulfur mass-independent isotope effect in photoexcitation of SO2 and the implications to the early earth's atmosphere. Proc Natl Acad Sci U S A 2013; 110:17697-702. [PMID: 23836655 DOI: 10.1073/pnas.1306979110] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Signatures of mass-independent isotope fractionation (MIF) are found in the oxygen ((16)O,(17)O,(18)O) and sulfur ((32)S, (33)S, (34)S, (36)S) isotope systems and serve as important tracers of past and present atmospheric processes. These unique isotope signatures signify the breakdown of the traditional theory of isotope fractionation, but the physical chemistry of these isotope effects remains poorly understood. We report the production of large sulfur isotope MIF, with Δ(33)S up to 78‰ and Δ(36)S up to 110‰, from the broadband excitation of SO2 in the 250-350-nm absorption region. Acetylene is used to selectively trap the triplet-state SO2 ( (3)B1), which results from intersystem crossing from the excited singlet ( (1)A2/ (1)B1) states. The observed MIF signature differs considerably from that predicted by isotopologue-specific absorption cross-sections of SO2 and is insensitive to the wavelength region of excitation (above or below 300 nm), suggesting that the MIF originates not from the initial excitation of SO2 to the singlet states but from an isotope selective spin-orbit interaction between the singlet ( (1)A2/ (1)B1) and triplet ( (3)B1) manifolds. Calculations based on high-level potential energy surfaces of the multiple excited states show a considerable lifetime anomaly for (33)SO2 and (36)SO2 for the low vibrational levels of the (1)A2 state. These results demonstrate that the isotope selectivity of accidental near-resonance interactions between states is of critical importance in understanding the origin of MIF in photochemical systems.
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Sulfur isotopic fractionation in vacuum UV photodissociation of hydrogen sulfide and its potential relevance to meteorite analysis. Proc Natl Acad Sci U S A 2013; 110:17650-5. [PMID: 23431159 DOI: 10.1073/pnas.1213150110] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Select meteoritic classes possess mass-independent sulfur isotopic compositions in sulfide and organic phases. Photochemistry in the solar nebula has been attributed as a source of these anomalies. Hydrogen sulfide (H2S) is the most abundant gas-phase species in the solar nebula, and hence, photodissociation of H2S by solar vacuum UV (VUV) photons (especially by Lyman-α radiation) is a relevant process. Because of experimental difficulties associated with accessing VUV radiation, there is a paucity of data and a lack of theoretical basis to test the hypothesis of a photochemical origin of mass-independent sulfur. Here, we present multiisotopic measurements of elemental sulfur produced during the VUV photolysis of H2S. Mass-independent sulfur isotopic compositions are observed. The observed isotopic fractionation patterns are wavelength-dependent. VUV photodissociation of H2S takes place through several predissociative channels, and the measured mass-independent fractionation is most likely a manifestation of these processes. Meteorite sulfur data are discussed in light of the present experiments, and suggestions are made to guide future experiments and models.
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Chakraborty S, Davis RD, Ahmed M, Jackson TL, Thiemens MH. Oxygen isotope fractionation in the vacuum ultraviolet photodissociation of carbon monoxide: wavelength, pressure, and temperature dependency. J Chem Phys 2012; 137:024309. [PMID: 22803538 DOI: 10.1063/1.4730911] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Several absorption bands exist in the vacuum ultraviolet (VUV) region of carbon monoxide (CO). Emission spectra indicate that these bands are all predissociative. Experimental results of CO photodissociation by vacuum ultraviolet photons (90 to 108 nm; ∼13 to 11 eV) from the Advanced Light Source synchrotron by measurement of the oxygen isotopic composition of the products are presented here. A large (few hundred per mil) range of oxygen isotopic compositions are observed in the CO photodissociation product and are wavelength dependent. Slope values (δ('17)O/δ('18)O) ranging from 0.72 to 1.36 were observed in the oxygen three-isotope space (δ('18)O vs. δ('17)O), which anti-correlated with increasing synchrotron photon energy, and indicates a dependency on the upper electronic state specific dissociation dynamics (e.g., perturbation and coupling associated with a particular state). An unprecedented magnitude in isotope fractionation was observed for photodissociation at 105 and 107 nm and is found to be associated with accidental predissociation of the vibrational states (ν = 0 and 1) for the upper electronic state E(1)Π. A significant temperature dependency in oxygen isotopic fractionation was observed, indicating a rotational level dependency in the predissociation process.
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Affiliation(s)
- Subrata Chakraborty
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0356, USA.
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Muskatel BH, Remacle F, Levine RD. Ultrafast Predissociation Mechanism of the 1Πu States of 14N2 and Its Isotopomers upon Attosecond Excitation from the Ground State. J Phys Chem A 2012; 116:11311-8. [DOI: 10.1021/jp305354h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- B. H. Muskatel
- The Fritz Haber Research Center, Hebrew University, Jerusalem 91904, Israel
| | - F. Remacle
- The Fritz Haber Research Center, Hebrew University, Jerusalem 91904, Israel
- Director FNRS, Department
of Chemistry, B6c, University of Liege, B4000 Liege, Belgium
| | - R. D. Levine
- The Fritz Haber Research Center, Hebrew University, Jerusalem 91904, Israel
- Department of Chemistry
and Biochemistry, Crump Institute for Molecular Imaging,
and Department of Molecular and Medical Pharmacology, University of California, Los Angeles,
California 90095, United States
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Thiemens MH, Chakraborty S, Dominguez G. The Physical Chemistry of Mass-Independent Isotope Effects and Their Observation in Nature. Annu Rev Phys Chem 2012; 63:155-77. [DOI: 10.1146/annurev-physchem-032511-143657] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Historically, the physical chemistry of isotope effects and precise measurements in samples from nature have provided information on processes that could not have been obtained otherwise. With the discovery of a mass-independent isotopic fractionation during the formation of ozone, a new physical chemical basis for isotope effects required development. Combined theoretical and experimental developments have broadened this understanding and extended the range of chemical systems where these unique effects occur. Simultaneously, the application of mass-independent isotopic measurements to an extensive range of both terrestrial and extraterrestrial systems has furthered the understanding of events such as solar system origin and evolution and planetary atmospheric chemistry, present and past.
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Affiliation(s)
- Mark H. Thiemens
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093;,
| | - Subrata Chakraborty
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093;,
| | - Gerardo Dominguez
- Department of Physics, California State University, San Marcos, San Marcos, California 92096
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Gao H, Yang L, Pan Y, Zhou J, Ng CY, Jackson WM. Time-sliced velocity-mapped imaging studies of the predissociation of single ro-vibronic energy levels of N2 in the extreme ultraviolet region using vacuum ultraviolet photoionization. J Chem Phys 2011; 135:134319. [PMID: 21992317 DOI: 10.1063/1.3644778] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The predissociation of N(2) from the rotational levels in the o(1)∏(u) (v(') = 2) and b(') (1)Σ(u) (v(') = 8) bands has been studied in the wavenumber (or energy) range from 109 350 cm(-1) (13.5577 eV) to 109 580 cm(-1) (13.5862 eV) by time-sliced velocity-mapped imaging technique with VUV photoionization detection of the fragments. These levels were excited from the ground state of N(2) (X(1)Σ(g) (+), v(") = 0) levels using an unfocused vacuum ultraviolet (VUV) laser via a one-photon process. The same VUV laser is used to ionize the metastable N ((2)D(o)) produced from the predissociation process and the time-sliced velocity-mapped imaging technique is used to determine their velocity and angular distributions. Two different theoretical methods developed, respectively, by Kim et al. [J. Chem. Phys. 125, 133316 (2006) and Zande [J. Chem. Phys. 107, 9447 (1997)] were used to calculate the anisotropic parameters for the predissociation to the channel N((4)S(o)) + N((2)D(o)) to compare with the observed value for each of the rotational levels. Very good agreement with the experimental results was obtained for both methods. Possible predissociation mechanisms were predicted from the measurements and calculations.
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Affiliation(s)
- Hong Gao
- Department of Chemistry, University of California, Davis, Davis, California 95616, USA
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