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Spiekermann G, Sahle CJ, Niskanen J, Gilmore K, Petitgirard S, Sternemann C, Tse JS, Murakami M. Sensitivity of the Kβ″ X-ray Emission Line to Coordination Changes in GeO 2 and TiO 2. J Phys Chem Lett 2023; 14:1848-1853. [PMID: 36779679 PMCID: PMC9940287 DOI: 10.1021/acs.jpclett.3c00017] [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: 01/03/2023] [Accepted: 02/07/2023] [Indexed: 06/18/2023]
Abstract
The hard X-ray Kβ″ emission line shows sensitivity with respect to a wide range of cation-ligand coordination, which we investigate in the cases of GeO2 and TiO2 on the basis of ab initio spectral calculations on amorphous and crystalline structures. In compressed amorphous GeO2, the sampling of a large number of instantaneous coordination polyhedra from an ab initio molecular dynamics trajectory reveals that the functional relation between the Kβ″ shift and coordination is close to linear between 4-fold and 7-fold coordination. A similar sensitivity of the Kβ″ emission line exists in the coordination range between six and nine of crystalline high-pressure TiO2 polymorphs. Our results demonstrate the potential of the Kβ″ emission line in research on the structure of amorphous oxide material.
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Affiliation(s)
| | - Ch. J. Sahle
- European
Synchrotron Radiation Facility (ESRF), 71 Avenue des Martyrs, 38000 Grenoble, France
| | - J. Niskanen
- Department
of Physics and Astronomy, University of
Turku, 20014 Turun yliopisto, Finland
| | - K. Gilmore
- Physics
Department and IRIS Adlershof, Humboldt
Universität zu Berlin, Zum grossen Windkanal 2, 12489 Berlin, Germany
| | | | - C. Sternemann
- Technische
Universität Dortmund, Fakultät Physik/DELTA, Maria-Goeppert-Mayer-Strasse 2, 44227 Dortmund, Germany
| | - J. S. Tse
- Department
of Physics and Engineering Physics, University
of Saskatchewan, Saskatoon S7N 5E2, Canada
| | - M. Murakami
- ETH
Zürich, Rämistrasse 101, 8092 Zürich, Switzerland
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2
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Klein IM, Liu H, Nimlos D, Krotz A, Cushing SK. Ab Initio Prediction of Excited-State and Polaron Effects in Transient XUV Measurements of α-Fe 2O 3. J Am Chem Soc 2022; 144:12834-12841. [PMID: 35816667 DOI: 10.1021/jacs.2c03994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Transient X-ray and extreme ultraviolet (XUV) spectroscopies have become invaluable tools for studying photoexcited dynamics due to their sensitivity to carrier occupations and local chemical or structural changes. One of the most studied materials using transient XUV spectroscopy is α-Fe2O3 because of its rich photoexcited dynamics, including small polaron formation. The interpretation of carrier and polaron effects in α-Fe2O3 is currently carried out using a semi-empirical method that is not transferrable to most materials. Here, an ab initio, Bethe-Salpeter equation (BSE) approach is developed that can incorporate photoexcited-state effects into arbitrary material systems. The accuracy of this approach is proven by calculating the XUV absorption spectra for the ground, photoexcited, and polaron states of α-Fe2O3. Furthermore, the theoretical approach allows for the projection of the core-valence excitons and different components of the X-ray transition Hamiltonian onto the band structure, providing new insights into old measurements. From this information, a physical intuition about the origins and nature of the transient XUV spectra can be built. A route to extracting electron and hole energies is even shown possible for highly angular momentum split XUV peaks. This method is easily generalized to K, L, M, and N edges to provide a general approach for analyzing transient X-ray absorption or reflection data.
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Affiliation(s)
- Isabel M Klein
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Hanzhe Liu
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Danika Nimlos
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Alex Krotz
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Scott Kevin Cushing
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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3
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Beckhoff B. Traceable Characterization of Nanomaterials by X-ray Spectrometry Using Calibrated Instrumentation. NANOMATERIALS 2022; 12:nano12132255. [PMID: 35808090 PMCID: PMC9268651 DOI: 10.3390/nano12132255] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 05/27/2022] [Accepted: 06/12/2022] [Indexed: 11/16/2022]
Abstract
Traceable characterization methods allow for the accurate correlation of the functionality or toxicity of nanomaterials with their underlaying chemical, structural or physical material properties. These correlations are required for the directed development of nanomaterials to reach target functionalities such as conversion efficiencies or selective sensitivities. The reliable characterization of nanomaterials requires techniques that often need to be adapted to the nano-scaled dimensions of the samples with respect to both the spatial dimensions of the probe and the instrumental or experimental discrimination capability. The traceability of analytical methods revealing information on chemical material properties relies on reference materials or qualified calibration samples, the spatial elemental distributions of which must be very similar to the nanomaterial of interest. At the nanoscale, however, only few well-known reference materials exist. An alternate route to establish the required traceability lays in the physical calibration of the analytical instrument’s response behavior and efficiency in conjunction with a good knowledge of the various interaction probabilities. For the elemental analysis, speciation, and coordination of nanomaterials, such a physical traceability can be achieved with X-ray spectrometry. This requires the radiometric calibration of energy- and wavelength-dispersive X-ray spectrometers, as well as the reliable determination of atomic X-ray fundamental parameters using such instrumentation. In different operational configurations, the information depths, discrimination capability, and sensitivity of X-ray spectrometry can be considerably modified while preserving its traceability, allowing for the characterization of surface contamination as well as interfacial thin layer and nanoparticle chemical compositions. Furthermore, time-resolved and hybrid approaches provide access to analytical information under operando conditions or reveal dimensional information, such as elemental or species depth profiles of nanomaterials. The aim of this review is to demonstrate the absolute quantification capabilities of SI-traceable X-ray spectrometry based upon calibrated instrumentation and knowledge about X-ray interaction probabilities.
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Affiliation(s)
- Burkhard Beckhoff
- Physikalisch-Technische Bundesanstalt, Abbestraße 2-12, 10587 Berlin, Germany
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4
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Holden WM, Jahrman EP, Govind N, Seidler GT. Probing Sulfur Chemical and Electronic Structure with Experimental Observation and Quantitative Theoretical Prediction of Kα and Valence-to-Core Kβ X-ray Emission Spectroscopy. J Phys Chem A 2020; 124:5415-5434. [PMID: 32486638 DOI: 10.1021/acs.jpca.0c04195] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
An extensive experimental and theoretical study of the Kα and Kβ high-resolution X-ray emission spectroscopy (XES) of sulfur-bearing systems is presented. This study encompasses a wide range of organic and inorganic compounds, including numerous experimental spectra from both prior published work and new measurements. Employing a linear-response time-dependent density functional theory (LR-TDDFT) approach, strong quantitative agreement is found in the calculation of energy shifts of the core-to-core Kα as well as the full range of spectral features in the valence-to-core Kβ spectrum. The ability to accurately calculate the sulfur Kα energy shift supports the use of sulfur Kα XES as a bulk-sensitive tool for assessing sulfur speciation. The fine structure of the sulfur Kβ spectrum, in conjunction with the theoretical results, is shown to be sensitive to the local electronic structure including effects of symmetry, ligand type and number, and, in the case of organosulfur compounds, to the nature of the bonded organic moiety. This agreement between theory and experiment, augmented by the potential for high-access XES measurements with the latest generation of laboratory-based spectrometers, demonstrates the possibility of broad analytical use of XES for sulfur and nearby third-row elements. The effective solution of the forward problem, i.e., successful prediction of detailed spectra from known molecular structure, also suggests future use of supervised machine learning approaches to experimental inference, as has seen recent interest for interpretation of X-ray absorption near-edge structure (XANES).
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Affiliation(s)
- William M Holden
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Evan P Jahrman
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Niranjan Govind
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
| | - Gerald T Seidler
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
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Wansleben M, Vinson J, Wählisch A, Bzheumikhova K, Hönicke P, Beckhoff B, Kayser Y. Speciation of iron sulfide compounds by means of X-ray Emission Spectroscopy using a compact full-cylinder von Hamos spectrometer. JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY 2020; 35:10.1039/d0ja00244e. [PMID: 34092880 PMCID: PMC8176736 DOI: 10.1039/d0ja00244e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We present experimental and theoretical X-ray emission spectroscopy (XES) data of the Fe Kβ line for Iron(II)sulfide (FeS) and Iron(II)disulfide (FeS2). In comparison to X-ray absorption spectroscopy (XAS), XES offers different discrimination capabilities for chemical speciation, depending on the valence states of the compounds probed and, more importantly in view of a a broader, laboratory-based use, a larger flexibility with respect to the excitation source used. The experimental Fe Kβ XES data was measured using polychromatic X-ray radiation and a compact full-cylinder von Hamos spectrometer while the calculations were realized using the OCEAN code. The von Hamos spectrometer used is characterized by an energy window of up to 700 eV and a spectral resolving power of E/ΔE = 800. The large energy window at a single position of the spectrometer components is made profit of to circumvent the instrumental sensitivity of wavelength-dispersive spectrometers to sample positioning. This results in a robust energy scale which is used to compare experimental data with ab initio valence-to-core calculations, which are carried out using the ocean package. To validate the reliability of the ocean package for the two sample systems, near edge X-ray absorption fine structure measurements of the Fe K absorption edge are compared to theory using the same input parameters as in the case of the X-ray emission calculations. Based on the example of iron sulfide compounds, the combination of XES experiments and ocean calculations allows unravelling the electronic structure of different transition metal sulfides and qualifying XES investigations for the speciation of different compounds.
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Affiliation(s)
- Malte Wansleben
- Physikalisch-Technische Bundesanstalt, Abbestraße 2-12, 10587 Berlin, Germany
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - John Vinson
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - André Wählisch
- Physikalisch-Technische Bundesanstalt, Abbestraße 2-12, 10587 Berlin, Germany
| | - Karina Bzheumikhova
- Physikalisch-Technische Bundesanstalt, Abbestraße 2-12, 10587 Berlin, Germany
| | - Philipp Hönicke
- Physikalisch-Technische Bundesanstalt, Abbestraße 2-12, 10587 Berlin, Germany
| | - Burkhard Beckhoff
- Physikalisch-Technische Bundesanstalt, Abbestraße 2-12, 10587 Berlin, Germany
| | - Yves Kayser
- Physikalisch-Technische Bundesanstalt, Abbestraße 2-12, 10587 Berlin, Germany
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Rani S, Lee JH, Kim Y. 200-mm segmented cylindrical figured crystal for von Hamos x-ray spectrometer. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:013101. [PMID: 32012639 DOI: 10.1063/1.5115321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 12/11/2019] [Indexed: 06/10/2023]
Abstract
A von Hamos Bragg crystal spectrometer at 1C beamline of Pohang Accelerator Laboratory for x-ray emission spectroscopy (XES) is described. Diced Si crystals of different orientations ([111], [110], [100], and [311]) are glued onto a planoconcave glass substrate having 250/500 mm radius of curvature. To enhance the spectrometer efficiency, the length of the crystal analyzer is kept 200 mm. The emission spectra of Cu foil and Fe foil and elastic scattering from Al foil are measured using the von Hamos geometry in which curved crystals disperse the x-rays. Spectrometer efficiency and energy resolution are measured at various x-ray photon energies. X-rays are incident at 6.54 keV, 9.00 keV, 9.205 keV, and 11.51 keV for Si(440), Si(444), Si(800), and Si(933) crystal analyzers, respectively. The cylindrical figured analyzer is placed near 80° with respect to the sample, which gives better energy resolution. The spectrometer efficiency of the Si(444) crystal analyzer increases by ∼2 times when the length of the analyzer is increased from 100 mm to 200 mm. Furthermore, to measure Fe Kα1, Kα2, and Kβ simultaneously, we made a mixed crystal analyzer in which alternative strips of Si[111] and Si[110] are glued onto one preshaped cylindrical substrate. The enhanced efficiency and simultaneous measurement of Kα and Kβ emission lines will give an edge over in situ and time-resolved x-ray emission spectroscopy studies. The information extracted with a high efficiency spectrometer from low intensity XES emission lines will be useful for the in situ elemental characterization in catalytic reactions.
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Affiliation(s)
- Sunita Rani
- Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang, Gyeongbuk 37673, South Korea
| | - Jae Hyuk Lee
- Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang, Gyeongbuk 37673, South Korea
| | - Yongsam Kim
- Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang, Gyeongbuk 37673, South Korea
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