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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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Ditter AS, Holden WM, Cary SK, Mocko V, Latimer MJ, Nelson EJ, Kozimor SA, Seidler GT. Resonant inelastic X-ray scattering using a miniature dispersive Rowland refocusing spectrometer. JOURNAL OF SYNCHROTRON RADIATION 2020; 27:446-454. [PMID: 32153283 PMCID: PMC7064111 DOI: 10.1107/s1600577520001022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 01/25/2020] [Indexed: 06/07/2023]
Abstract
X-ray absorption spectroscopy (XAS) beamlines worldwide are steadily increasing their emphasis on full photon-in/photon-out spectroscopies, such as resonant inelastic X-ray scattering (RIXS), resonant X-ray emission spectroscopy (RXES) and high energy resolution fluorescence detection XAS (HERFD-XAS). In such cases, each beamline must match the choice of emission spectrometer to the scientific mission of its users. Previous work has recently reported a miniature tender X-ray spectrometer using a dispersive Rowland refocusing (DRR) geometry that functions with high energy resolution even with a large X-ray spot size on the sample [Holden et al. (2017). Rev. Sci. Instrum. 88, 073904]. This instrument has been used in the laboratory in multiple studies of non-resonant X-ray emission spectroscopy using a conventional X-ray tube, though only for preliminary measurements at a low-intensity microfocus synchrotron beamline. This paper reports an extensive study of the performance of a miniature DRR spectrometer at an unfocused wiggler beamline, where the incident monochromatic flux allows for resonant studies which are impossible in the laboratory. The results support the broader use of the present design and also suggest that the DRR method with an unfocused beam could have important applications for materials with low radiation damage thresholds and that would not survive analysis on focused beamlines.
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Affiliation(s)
- Alexander S. Ditter
- Department of Physics, University of Washington, PO Box 351650, Seattle, WA 98195-1560, USA
- C-IIAC, Los Alamos National Laboratory, PO Box 1663, Los Alamos, NM 87545, USA
| | - William M. Holden
- Department of Physics, University of Washington, PO Box 351650, Seattle, WA 98195-1560, USA
| | - Samantha K. Cary
- C-IIAC, Los Alamos National Laboratory, PO Box 1663, Los Alamos, NM 87545, USA
| | - Veronika Mocko
- C-IIAC, Los Alamos National Laboratory, PO Box 1663, Los Alamos, NM 87545, USA
| | - Matthew J. Latimer
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Erik J. Nelson
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Stosh A. Kozimor
- C-IIAC, Los Alamos National Laboratory, PO Box 1663, Los Alamos, NM 87545, USA
| | - Gerald T. Seidler
- Department of Physics, University of Washington, PO Box 351650, Seattle, WA 98195-1560, USA
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Jahrman EP, Holden WM, Ditter AS, Mortensen DR, Seidler GT, Fister TT, Kozimor SA, Piper LFJ, Rana J, Hyatt NC, Stennett MC. An improved laboratory-based x-ray absorption fine structure and x-ray emission spectrometer for analytical applications in materials chemistry research. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:024106. [PMID: 30831699 DOI: 10.1063/1.5049383] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 02/01/2019] [Indexed: 06/09/2023]
Abstract
X-ray absorption fine structure (XAFS) and x-ray emission spectroscopy (XES) are advanced x-ray spectroscopies that impact a wide range of disciplines. However, unlike the majority of other spectroscopic methods, XAFS and XES are accompanied by an unusual access model, wherein the dominant use of the technique is for premier research studies at world-class facilities, i.e., synchrotron x-ray light sources. In this paper, we report the design and performance of an improved XAFS and XES spectrometer based on the general conceptual design of Seidler et al. [Rev. Sci. Instrum. 85, 113906 (2014)]. New developments include reduced mechanical degrees of freedom, much-increased flux, and a wider Bragg angle range to enable extended x-ray absorption fine structure (EXAFS) measurement and analysis for the first time with this type of modern laboratory XAFS configuration. This instrument enables a new class of routine applications that are incompatible with the mission and access model of the synchrotron light sources. To illustrate this, we provide numerous examples of x-ray absorption near edge structure (XANES), EXAFS, and XES results for a variety of problems and energy ranges. Highlights include XAFS and XES measurements of battery electrode materials, EXAFS of Ni with full modeling of results to validate monochromator performance, valence-to-core XES for 3d transition metal compounds, and uranium XANES and XES for different oxidation states. Taken en masse, these results further support the growing perspective that modern laboratory-based XAFS and XES have the potential to develop a new branch of analytical chemistry.
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Affiliation(s)
- Evan P Jahrman
- Physics Department, University of Washington, Seattle, Washington 98195-1560, USA
| | - William M Holden
- Physics Department, University of Washington, Seattle, Washington 98195-1560, USA
| | - Alexander S Ditter
- Physics Department, University of Washington, Seattle, Washington 98195-1560, USA
| | - Devon R Mortensen
- Physics Department, University of Washington, Seattle, Washington 98195-1560, USA
| | - Gerald T Seidler
- Physics Department, University of Washington, Seattle, Washington 98195-1560, USA
| | - Timothy T Fister
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Stosh A Kozimor
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Louis F J Piper
- Department of Physics, Binghamton University, Binghamton, New York 13902, USA
| | - Jatinkumar Rana
- Department of Physics, Binghamton University, Binghamton, New York 13902, USA
| | - Neil C Hyatt
- Materials Science and Engineering Department, The University of Sheffield, Mapping Street, Sheffield S1 3JD, United Kingdom
| | - Martin C Stennett
- Materials Science and Engineering Department, The University of Sheffield, Mapping Street, Sheffield S1 3JD, United Kingdom
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Jahrman EP, Holden WM, Ditter AS, Kozimor SA, Kihara SL, Seidler GT. Vacuum formed temporary spherically and toroidally bent crystal analyzers for x-ray absorption and x-ray emission spectroscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:013106. [PMID: 30709184 DOI: 10.1063/1.5057231] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 12/17/2018] [Indexed: 06/09/2023]
Abstract
We demonstrate that vacuum forming of 10-cm diameter silicon wafers of various crystallographic orientations under an x-ray permeable, flexible window can easily generate spherically bent crystal analyzers and toroidally bent crystal analyzers with ∼1-eV energy resolution and a 1-m major radius of curvature. In applications at synchrotron light sources, x-ray free electron lasers, and laboratory spectrometers, these characteristics are generally sufficient for many x-ray absorption fine structure (XAFS), x-ray emission spectroscopy (XES), and resonant inelastic x-ray scattering applications in the chemical sciences. Unlike existing optics manufacturing methods using epoxy or anodic bonding, vacuum forming without adhesive is temporary in the sense that the bent wafer can be removed when vacuum is released and exchanged for a different orientation wafer. Therefore, the combination of an x-ray compatible vacuum-forming chamber, a library of thin wafers, and a small number of forms having different secondary curvatures can give extreme flexibility in spectrometer energy range. As proof of this method, we determine the energy resolution and reflectivity for several such vacuum-formed bent crystal analyzers in laboratory-based XAFS and XES studies using a conventional x-ray tube. For completeness, we also show x-ray images collected on the detector plane to characterize the resulting focal spots and optical aberrations.
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Affiliation(s)
- Evan P Jahrman
- Physics Department, University of Washington, Seattle, Washington 98195, USA
| | - William M Holden
- Physics Department, University of Washington, Seattle, Washington 98195, USA
| | - Alexander S Ditter
- Physics Department, University of Washington, Seattle, Washington 98195, USA
| | - Stosh A Kozimor
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Scott L Kihara
- Physics Department, University of Washington, Seattle, Washington 98195, USA
| | - Gerald T Seidler
- Physics Department, University of Washington, Seattle, Washington 98195, USA
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