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Dupuy R, Buttersack T, Trinter F, Richter C, Gholami S, Björneholm O, Hergenhahn U, Winter B, Bluhm H. The solvation shell probed by resonant intermolecular Coulombic decay. Nat Commun 2024; 15:6926. [PMID: 39138192 PMCID: PMC11322543 DOI: 10.1038/s41467-024-51417-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Accepted: 08/06/2024] [Indexed: 08/15/2024] Open
Abstract
Molecules involved in solvation shells have properties differing from those of the bulk solvent, which can in turn affect reactivity. Among key properties of these molecules are their nature and electronic structure. Widely used tools to characterize this type of property are X-ray-based spectroscopies, which, however, usually lack the capability to selectively probe the solvation-shell molecules. A class of X-ray triggered "non-local" processes has the recognized potential to provide this selectivity. Intermolecular Coulombic decay (ICD) and related processes involve neighbouring molecules in the decay of the X-ray-excited target, and are thus naturally sensitive to its immediate environment. Applying electron spectroscopy to aqueous solutions, we explore the resonant flavours of ICD and demonstrate how it can inform on the first solvation shell of excited solvated cations. One particular ICD process turns out to be a potent marker of the formation of ion pairs. Another gives a direct access to the electron binding energies of the water molecules in the first solvation shell, a quantity previously elusive to direct measurements. The resonant nature of the processes makes them readily measurable, providing powerful new spectroscopic tools.
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Affiliation(s)
- Rémi Dupuy
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany.
- Sorbonne Université, CNRS, Laboratoire de Chimie Physique - Matiere et Rayonnement, LCPMR, F-75005, Paris Cedex 05, France.
| | - Tillmann Buttersack
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
| | - Florian Trinter
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
- Institut für Kernphysik, Goethe-Universität Frankfurt, Max-von-Laue-Str. 1, 60438, Frankfurt am Main, Germany
| | - Clemens Richter
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
| | - Shirin Gholami
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
| | - Olle Björneholm
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20, Uppsala, Sweden
| | - Uwe Hergenhahn
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
| | - Bernd Winter
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
| | - Hendrik Bluhm
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
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2
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Ermolaev GA, Voronin KV, Toksumakov AN, Grudinin DV, Fradkin IM, Mazitov A, Slavich AS, Tatmyshevskiy MK, Yakubovsky DI, Solovey VR, Kirtaev RV, Novikov SM, Zhukova ES, Kruglov I, Vyshnevyy AA, Baranov DG, Ghazaryan DA, Arsenin AV, Martin-Moreno L, Volkov VS, Novoselov KS. Wandering principal optical axes in van der Waals triclinic materials. Nat Commun 2024; 15:1552. [PMID: 38448442 PMCID: PMC10918091 DOI: 10.1038/s41467-024-45266-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 01/19/2024] [Indexed: 03/08/2024] Open
Abstract
Nature is abundant in material platforms with anisotropic permittivities arising from symmetry reduction that feature a variety of extraordinary optical effects. Principal optical axes are essential characteristics for these effects that define light-matter interaction. Their orientation - an orthogonal Cartesian basis that diagonalizes the permittivity tensor, is often assumed stationary. Here, we show that the low-symmetry triclinic crystalline structure of van der Waals rhenium disulfide and rhenium diselenide is characterized by wandering principal optical axes in the space-wavelength domain with above π/2 degree of rotation for in-plane components. In turn, this leads to wavelength-switchable propagation directions of their waveguide modes. The physical origin of wandering principal optical axes is explained using a multi-exciton phenomenological model and ab initio calculations. We envision that the wandering principal optical axes of the investigated low-symmetry triclinic van der Waals crystals offer a platform for unexplored anisotropic phenomena and nanophotonic applications.
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Affiliation(s)
- Georgy A Ermolaev
- Emerging Technologies Research Center, XPANCEO, Dubai Investment Park First, Dubai, United Arab Emirates
| | - Kirill V Voronin
- Donostia International Physics Center (DIPC), Donostia/San Sebastián, 20018, Spain
| | - Adilet N Toksumakov
- Moscow Center for Advanced Studies, Kulakova str. 20, Moscow, 123592, Russia
| | - Dmitriy V Grudinin
- Emerging Technologies Research Center, XPANCEO, Dubai Investment Park First, Dubai, United Arab Emirates
| | - Ilia M Fradkin
- Emerging Technologies Research Center, XPANCEO, Dubai Investment Park First, Dubai, United Arab Emirates
| | - Arslan Mazitov
- Institute of Materials, École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland
| | - Aleksandr S Slavich
- Moscow Center for Advanced Studies, Kulakova str. 20, Moscow, 123592, Russia
| | | | - Dmitry I Yakubovsky
- Moscow Center for Advanced Studies, Kulakova str. 20, Moscow, 123592, Russia
| | - Valentin R Solovey
- Emerging Technologies Research Center, XPANCEO, Dubai Investment Park First, Dubai, United Arab Emirates
| | - Roman V Kirtaev
- Emerging Technologies Research Center, XPANCEO, Dubai Investment Park First, Dubai, United Arab Emirates
| | - Sergey M Novikov
- Moscow Center for Advanced Studies, Kulakova str. 20, Moscow, 123592, Russia
| | - Elena S Zhukova
- Moscow Center for Advanced Studies, Kulakova str. 20, Moscow, 123592, Russia
| | - Ivan Kruglov
- Emerging Technologies Research Center, XPANCEO, Dubai Investment Park First, Dubai, United Arab Emirates
| | - Andrey A Vyshnevyy
- Emerging Technologies Research Center, XPANCEO, Dubai Investment Park First, Dubai, United Arab Emirates
| | - Denis G Baranov
- Moscow Center for Advanced Studies, Kulakova str. 20, Moscow, 123592, Russia
| | - Davit A Ghazaryan
- Moscow Center for Advanced Studies, Kulakova str. 20, Moscow, 123592, Russia
- Laboratory of Advanced Functional Materials, Yerevan State University, Yerevan, 0025, Armenia
| | - Aleksey V Arsenin
- Emerging Technologies Research Center, XPANCEO, Dubai Investment Park First, Dubai, United Arab Emirates
- Laboratory of Advanced Functional Materials, Yerevan State University, Yerevan, 0025, Armenia
| | - Luis Martin-Moreno
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009, Zaragoza, Spain
- Departamento de Física de la Materia Condensada, Universidad de Zaragoza, 50009, Zaragoza, Spain
| | - Valentyn S Volkov
- Emerging Technologies Research Center, XPANCEO, Dubai Investment Park First, Dubai, United Arab Emirates
- Laboratory of Advanced Functional Materials, Yerevan State University, Yerevan, 0025, Armenia
| | - Kostya S Novoselov
- National Graphene Institute (NGI), University of Manchester, Manchester, M13 9PL, UK.
- Department of Materials Science and Engineering, National University of Singapore, Singapore, 03-09, Singapore.
- Institute for Functional Intelligent Materials, National University of Singapore, 117544, Singapore, Singapore.
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3
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Deng X, Zheng C, Li Y, Zhou Z, Wang J, Ran Y, Hu Z, Yang F, Li L. Conductive catalysis by subsurface transition metals. Natl Sci Rev 2024; 11:nwae015. [PMID: 38328681 PMCID: PMC10849361 DOI: 10.1093/nsr/nwae015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 09/21/2023] [Accepted: 09/22/2023] [Indexed: 02/09/2024] Open
Abstract
The nature of catalysis has been hotly pursued for over a century, and current research is focused on understanding active centers and their electronic structures. Herein, the concept of conductive catalysis is proposed and verified by theoretical simulations and experimental observations. Metallic systems containing buried catalytically active transitional metals and exposed catalytically inert main group metals are constructed, and the electronic interaction between them via metallic bonding is disclosed. Through the electronic interaction, the catalytic properties of subsurface transitional metals (Pd or Rh) can be transferred to outermost main group metals (Al or Mg) for several important transformations like semi-hydrogenation, Suzuki-coupling and hydroformylation. The catalytic force is conductive, in analogy with the magnetic force and electrostatic force. The traditional definition of active centers is challenged by the concept of conductive catalysis and the electronic nature of catalysis is more easily understood. It might provide new opportunities for shielding traditional active centers against poisoning or leaching and allow for precise regulation of their catalytic properties by the conductive layer.
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Affiliation(s)
- Xin Deng
- Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Caiyan Zheng
- School of Physics, Nankai University, Tianjin 300071, China
| | - Yangsheng Li
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Zeyu Zhou
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Jiamin Wang
- School of Materials Science and Engineering, Nankai University, Tianjin 300350, China
| | - Yihua Ran
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Zhenpeng Hu
- School of Physics, Nankai University, Tianjin 300071, China
| | - Fan Yang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Landong Li
- Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, China
- School of Materials Science and Engineering, Nankai University, Tianjin 300350, China
- Haihe Laboratory of Sustainable Chemical Transformations, Tianjin 300192, China
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Mato J, Willow SY, Werhahn JC, Xantheas SS. The Back Door to the Surface Hydrated Electron. J Phys Chem Lett 2023; 14:8221-8226. [PMID: 37672781 DOI: 10.1021/acs.jpclett.3c01479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/08/2023]
Abstract
We use a Mg+ metal to extend the size regime of aqueous clusters to extrapolate to the bulk limit of the vertical detachment energy (VDE) of the solvated electron to >3,200, a value between 1 to over 2 orders of magnitude larger than the one previously measured experimentally or computed theoretically. We relate the VDE to the energy difference between the Mg+(H2O)n and Mg2+(H2O)n systems and the metal's second ionization potential. The extrapolated bulk VDEs of the localized surface electron, which moves away from the metal as n increases, are 1.89 ± 0.01 eV for semiempirical (n ∼ 3,200; PM6-D3H4) and 1.73 ± 0.03 eV (n ∼ 150; HF) and 1.83 ± 0.02 eV (n ∼ 150; MP2) for ab initio, in excellent agreement with the 1.6-1.8 eV range of experimental results. The VDEs converge from above (larger values) to the bulk limit, in a manner that is qualitatively opposite from previous studies and experiments lacking a charged metal, a fact justifying the "back door" approach to the solvated electron.
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Affiliation(s)
- Joani Mato
- Physical Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MS J7-10, Richland, Washington 99352, United States
| | - Soohaeng Yoo Willow
- Department of Energy Science, Sungkyunkwan University, Seobu-ro 2066, Suwon 16419, Republic of Korea
| | - Jasper C Werhahn
- Department of Physics E11, Technical University of Munich, James-Franck-Strasse, D-85748 Garching, Germany
| | - Sotiris S Xantheas
- Advanced Computing, Mathematics and Data Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MS J7-10, Richland, Washington 99352, United States
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
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5
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Pugini M, Credidio B, Walter I, Malerz S, Trinter F, Stemer D, Hergenhahn U, Meijer G, Wilkinson I, Winter B, Thürmer S. How to measure work functions from aqueous solutions. Chem Sci 2023; 14:9574-9588. [PMID: 37712029 PMCID: PMC10498509 DOI: 10.1039/d3sc01740k] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 07/28/2023] [Indexed: 09/16/2023] Open
Abstract
The recent application of concepts from condensed-matter physics to photoelectron spectroscopy (PES) of volatile, liquid-phase systems has enabled the measurement of electronic energetics of liquids on an absolute scale. Particularly, vertical ionization energies, VIEs, of liquid water and aqueous solutions, both in the bulk and at associated interfaces, can now be accurately, precisely, and routinely determined. These IEs are referenced to the local vacuum level, which is the appropriate quantity for condensed matter with associated surfaces, including liquids. In this work, we connect this newly accessible energy level to another important surface property, namely, the solution work function, eΦliq. We lay out the prerequisites for and unique challenges of determining eΦ of aqueous solutions and liquids in general. We demonstrate - for a model aqueous solution with a tetra-n-butylammonium iodide (TBAI) surfactant solute - that concentration-dependent work functions, associated with the surface dipoles generated by the segregated interfacial layer of TBA+ and I- ions, can be accurately measured under controlled conditions. We detail the nature of surface potentials, uniquely tied to the nature of the flowing-liquid sample, which must be eliminated or quantified to enable such measurements. This allows us to refer aqueous-phase spectra to the Fermi level and to quantitatively assign surfactant-concentration-dependent spectral shifts to competing work function and electronic-structure effects, where the latter are typically associated with solute-solvent interactions in the bulk of the solution which determine, e.g., chemical reactivity. The present work describes the extension of liquid-jet PES to quantitatively access concentration-dependent surface descriptors that have so far been restricted to solid-phase measurements. Correspondingly, these studies mark the beginning of a new era in the characterization of the interfacial electronic structure of aqueous solutions and liquids more generally.
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Affiliation(s)
- Michele Pugini
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4-6 14195 Berlin Germany
| | - Bruno Credidio
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4-6 14195 Berlin Germany
| | - Irina Walter
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4-6 14195 Berlin Germany
| | - Sebastian Malerz
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4-6 14195 Berlin Germany
| | - Florian Trinter
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4-6 14195 Berlin Germany
- Institut für Kernphysik, Goethe-Universität Max-von-Laue-Straße 1 60438 Frankfurt am Main Germany
| | - Dominik Stemer
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4-6 14195 Berlin Germany
| | - Uwe Hergenhahn
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4-6 14195 Berlin Germany
| | - Gerard Meijer
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4-6 14195 Berlin Germany
| | - Iain Wilkinson
- Institute for Electronic Structure Dynamics, Helmholtz-Zentrum Berlin für Materialien und Energie Hahn-Meitner-Platz 1 14109 Berlin Germany
| | - Bernd Winter
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4-6 14195 Berlin Germany
| | - Stephan Thürmer
- Department of Chemistry, Graduate School of Science, Kyoto University Kitashirakawa-Oiwakecho, Sakyo-Ku 606-8502 Kyoto Japan
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Zhou YH, Yang SY, Wang MX, Guan YH, Ma J. Fast degradation of atrazine by nZVI-Cu 0/PMS: Re-evaluation and quantification of reactive species, generation pathways, and application feasibility. WATER RESEARCH 2023; 243:120311. [PMID: 37459795 DOI: 10.1016/j.watres.2023.120311] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 05/28/2023] [Accepted: 07/03/2023] [Indexed: 09/07/2023]
Abstract
Additive metal to zero-valent iron (ZVI) could enhance the reduction ability and the additive Cu0 was incorporated to ZVI to accelerate PMS activation with atrazine (ATZ) as target compound. The efficiencies of ATZ degradation and PMS decomposition climbed up firstly and then declined as Cu0 loading increased from 0.01 to 1.00 wt% with the maximums at 0.10 wt%. SO4•-, HO•, Fe(IV), O2•- and 1O2 were generated by nZVI-Cu0/PMS based on the results of electron paramagnetic resonance (EPR) and simultaneous degradation of nitrobenzene, ATZ, and methyl phenyl sulfoxide (PMSO). The rate constant of Fe(IV) and ATZ was estimated as 7 × 104 M-1∙s-1 via the variation of methyl phenyl sulfone (PMSO2)formation at different ATZ concentrations. However, Fe(IV) contributed negligibly to ATZ degradation due to the strong scavenging of Fe(IV) by PMS. SO4•- and HO• were the reactive species responsible for ATZ degradation and the yield ratio of SO4•- and HO• was about 8.70 at initial stage. Preliminary thermodynamic calculation on the possible activation ways revealed that the dominant production of SO4•- might originate from the atomic H reduction of PMS in the surface layer of nZVI-Cu0. Ten products of ATZ degradation were identified by HPLC/ESI/QTOF and the possible degradation pathways were analyzed combined with theoretical calculation on ATZ structure. The decrease of temperature or increase of solution pH led to the decline of ATZ degradation, as well as the individual addition of common ions (HCO3-, Cl-, SO42-, NH4+, NO3- and F-) and natural organic matters (NOM). In real water, ATZ was still efficiently degraded with the decontamination efficiency decreasing in the sequence of tap water > surface water > simulated wastewater > groundwater. For the treatment of ATZ-polluted continuous flow, nZVI-Cu0 in double-layer layout had a higher capacity than the single-layer mode. Meanwhile, the leaching TFe and TCu were limited. The results indicate nZVI-Cu0/PMS is applicable and the multiple-layer layout of nZVI-Cu0 is suggested for ATZ-polluted ground water and soil remediation.
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Affiliation(s)
- Yue-Han Zhou
- School of Water Conservancy and Civil Engineering, Northeast Agricultural University, Harbin 150030, China
| | - Song-Yu Yang
- School of Water Conservancy and Civil Engineering, Northeast Agricultural University, Harbin 150030, China
| | - Ming-Xuan Wang
- School of Water Conservancy and Civil Engineering, Northeast Agricultural University, Harbin 150030, China
| | - Ying-Hong Guan
- School of Water Conservancy and Civil Engineering, Northeast Agricultural University, Harbin 150030, China.
| | - Jun Ma
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
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7
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Jackson BA, Khan SN, Miliordos E. A fresh perspective on metal ammonia molecular complexes and expanded metals: opportunities in catalysis and quantum information. Chem Commun (Camb) 2023; 59:10572-10587. [PMID: 37555315 DOI: 10.1039/d3cc02956e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2023]
Abstract
Recent advances in our comprehension of the electronic structure of metal ammonia complexes have opened avenues for novel materials with diffuse electrons. These complexes in their ground state can host peripheral "Rydberg" electrons which populate a hydrogenic-type shell model imitating atoms. Aggregates of such complexes form the so-called expanded or liquid metals. Expanded metals composed of d- and f-block metal ammonia complexes offer properties, such as magnetic moments and larger numbers of diffuse electrons, not present for alkali and alkaline earth (s-block) metals. In addition, tethering metal ammonia complexes via hydrocarbon chains (replacement of ammonia ligands with diamines) yields materials that can be used for redox catalysis and quantum computing, sensing, and optics. This perspective summarizes the recent findings for gas-phase isolated metal ammonia complexes and projects the obtained knowledge to the condensed phase regime. Possible applications for the newly introduced expanded metals and linked solvated electrons precursors are discussed and future directions are proposed.
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Affiliation(s)
- Benjamin A Jackson
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849-5312, USA.
| | - Shahriar N Khan
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849-5312, USA.
| | - Evangelos Miliordos
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849-5312, USA.
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8
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A universal all-solid synthesis for high throughput production of halide perovskite. Nat Commun 2022; 13:7399. [PMID: 36456593 PMCID: PMC9715688 DOI: 10.1038/s41467-022-35122-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 11/18/2022] [Indexed: 12/04/2022] Open
Abstract
Halide perovskites show ubiquitous presences in growing fields at both fundamental and applied levels. Discovery, investigation, and application of innovative perovskites are heavily dependent on the synthetic methodology in terms of time-/yield-/effort-/energy- efficiency. Conventional wet chemistry method provides the easiness for growing thin film samples, but represents as an inefficient way for bulk crystal synthesis. To overcome these, here we report a universal solid state-based route for synthesizing high-quality perovskites, by means of simultaneously applying both electric and mechanical stress fields during the synthesis, i.e., the electrical and mechanical field-assisted sintering technique. We employ various perovskite compositions and arbitrary geometric designs for demonstration in this report, and establish such synthetic route with uniqueness of ultrahigh yield, fast processing and solvent-free nature, along with bulk products of exceptional quality approaching to single crystals. We exemplify the applications of the as-synthesized perovskites in photodetection and thermoelectric as well as other potentials to open extra chapters for future technical development.
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9
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Sala L, Luxford TFM, Ranković M, Kočišek J. Viewpoints on the 11th International Meeting on Atomic and Molecular Physics and Chemistry. J Phys Chem A 2022; 126:8557-8561. [DOI: 10.1021/acs.jpca.2c07768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Leo Sala
- J. Heyrovský Institute of Physical Chemistry v.v.i., The Czech Academy of Sciences, Dolejškova 3, 18223Prague, Czech Republic
| | - Thomas F. M. Luxford
- J. Heyrovský Institute of Physical Chemistry v.v.i., The Czech Academy of Sciences, Dolejškova 3, 18223Prague, Czech Republic
| | - Miloš Ranković
- J. Heyrovský Institute of Physical Chemistry v.v.i., The Czech Academy of Sciences, Dolejškova 3, 18223Prague, Czech Republic
| | - Jaroslav Kočišek
- J. Heyrovský Institute of Physical Chemistry v.v.i., The Czech Academy of Sciences, Dolejškova 3, 18223Prague, Czech Republic
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10
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Wright JR. A seismometer that can be used to study pre-quake signals. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:075103. [PMID: 35922287 DOI: 10.1063/5.0070885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 06/15/2022] [Indexed: 06/15/2023]
Abstract
The sensitive, broadband seismometer described in this paper is based on frequency modulation and a two-dimensional (2D) Fourier transform method to obtain time vs frequency (and seismic amplitude) recordings. The intent was to develop an instrument that could compare seismic recordings with variables (as signals) that, for rational reasons, might be active before a seismic rupture and, thus, possibly serve as quake warning indicators. Five such variables were eventually incorporated into the instrument and tested as amplitudes: electric field changes, the electromagnetic spectrum between 3 and 30 Hz (extremely low frequency as Schumann-like emissions), the electromagnetic spectrum between 0.3 and 3 Hz (possibly ionospheric Alfvén waves acting through the geomagnetic field), and short period seismic resonances at 10.1 and 15.9 Hz. All five of the sensors actually detected possible precursors of the seismic events that followed them. However, the 3-30 Hz electromagnetic signals showed up in less than 10% of the recorded earthquakes. The signals of the 0.3-3 Hz band were also not in all quake recordings. Broadband strobing was recorded before several earthquakes and was especially prominent for hours before a quake near Wyatt MO and Bardwell KY on 2017-03-19. The strobe issue appears to be worthy of further scrutiny. The lack of a good electric conduction mechanism between earthquake hypocenters and the earth-ionosphere cavity may be the reason why the Schumann-like emissions of the 3-30 Hz band were not observed for most earthquakes. A magnetometer is a preferred next step because it could increase the percentage of quakes with observable effects. In addition, a short period seismic resonator for 20 Hz is another desirable addition.
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Affiliation(s)
- John R Wright
- Chemistry, Computer, and Physical Science, Southeastern Oklahoma State University, 425 W. University Blvd., Durant, Oklahoma 74701, USA
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11
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Ariyarathna IR, Miliordos E. Ground and excited states analysis of alkali metal ethylenediamine and crown ether complexes. Phys Chem Chem Phys 2021; 23:20298-20306. [PMID: 34486608 DOI: 10.1039/d1cp02552j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
High-level electronic structure calculations are carried out to obtain optimized geometries and excitation energies of neutral lithium, sodium, and potassium complexes with two ethylenediamine and one or two crown ether molecules. Three different sizes of crowns are employed (12-crown-4, 15-crown-5, 18-crown-6). The ground state of all complexes contains an electron in an s-type orbital. For the mono-crown ether complexes, this orbital is the polarized valence s-orbital of the metal, but for the other systems this orbital is a peripheral diffuse orbital. The nature of the low-lying electronic states is found to be different for each of these species. Specifically, the metal ethylenediamine complexes follow the previously discovered shell model of metal ammonia complexes (1s, 1p, 1d, 2s, 1f), but both mono- and sandwich di-crown ether complexes bear a different shell model partially due to their lower (cylindrical) symmetry and the stabilization of the 2s-type orbital. Li(15-crown-5) is the only complex with the metal in the middle of the crown ether and adopts closely the shell model of metal ammonia complexes. Our findings suggest that the electronic band structure of electrides (metal crown ether sandwich aggregates) and expanded metals (metal ammonia aggregates) should be different despite the similar nature of these systems (bearing diffuse electrons around a metal complex).
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Affiliation(s)
- Isuru R Ariyarathna
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849-5312, USA.
| | - Evangelos Miliordos
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849-5312, USA.
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12
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Castelvecchi D. Water transformed into shiny, golden metal. Nature 2021; 596:18. [PMID: 34321648 DOI: 10.1038/d41586-021-02065-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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