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Abstract
We review oxygen K-edge X-ray absorption spectra of both molecules and solids. We start with an overview of the main experimental aspects of oxygen K-edge X-ray absorption measurements including X-ray sources, monochromators, and detection schemes. Many recent oxygen K-edge studies combine X-ray absorption with time and spatially resolved measurements and/or operando conditions. The main theoretical and conceptual approximations for the simulation of oxygen K-edges are discussed in the Theory section. We subsequently discuss oxygen atoms and ions, binary molecules, water, and larger molecules containing oxygen, including biomolecular systems. The largest part of the review deals with the experimental results for solid oxides, starting from s- and p-electron oxides. Examples of theoretical simulations for these oxides are introduced in order to show how accurate a DFT description can be in the case of s and p electron overlap. We discuss the general analysis of the 3d transition metal oxides including discussions of the crystal field effect and the effects and trends in oxidation state and covalency. In addition to the general concepts, we give a systematic overview of the oxygen K-edges element by element, for the s-, p-, d-, and f-electron systems.
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Affiliation(s)
- Federica Frati
- Inorganic
chemistry and catalysis, Debye Institute for Nanomaterials Science, Utrecht University, 3584CG Utrecht, The Netherlands
| | | | - Frank M. F. de Groot
- Inorganic
chemistry and catalysis, Debye Institute for Nanomaterials Science, Utrecht University, 3584CG Utrecht, The Netherlands
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2
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Golnak R, Xiao J, Atak K, Unger I, Seidel R, Winter B, Aziz EF. Undistorted X-ray Absorption Spectroscopy Using s-Core-Orbital Emissions. J Phys Chem A 2016; 120:2808-14. [PMID: 27101344 DOI: 10.1021/acs.jpca.6b01699] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Detection of secondary emissions, fluorescence yield (FY), or electron yield (EY), originating from the relaxation processes upon X-ray resonant absorption has been widely adopted for X-ray absorption spectroscopy (XAS) measurements when the primary absorption process cannot be probed directly in transmission mode. Various spectral distortion effects inherent in the relaxation processes and in the subsequent transportation of emitted particles (electron or photon) through the sample, however, undermine the proportionality of the emission signals to the X-ray absorption coefficient. In the present study, multiple radiative (FY) and nonradiative (EY) decay channels have been experimentally investigated on a model system, FeCl3 aqueous solution, at the excitation energy of the Fe L-edge. The systematic comparisons between the experimental spectra taken from various decay channels, as well as the comparison with the theoretically simulated Fe L-edge XA spectrum that involves only the absorption process, indicate that the detection of the Fe 3s → 2p partial fluorescence yield (PFY) gives rise to the true Fe L-edge XA spectrum. The two key characteristics generalized from this particular decay channel-zero orbital angular momentum (i.e., s orbital) and core-level emission-set a guideline for obtaining undistorted X-ray absorption spectra in the future.
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Affiliation(s)
- Ronny Golnak
- Institute of Methods for Material Development, Helmholtz-Zentrum Berlin für Materialien und Energie (HZB) , Albert-Einstein-Strasse 15, D-12489 Berlin, Germany.,Department of Chemistry, Free University Berlin , Takustrasse 3, 14195 Berlin, Germany
| | - Jie Xiao
- Institute of Methods for Material Development, Helmholtz-Zentrum Berlin für Materialien und Energie (HZB) , Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
| | - Kaan Atak
- Institute of Methods for Material Development, Helmholtz-Zentrum Berlin für Materialien und Energie (HZB) , Albert-Einstein-Strasse 15, D-12489 Berlin, Germany.,Department of Physics, Free University Berlin , Arnimallee 14, 14195 Berlin, Germany
| | - Isaak Unger
- Institute of Methods for Material Development, Helmholtz-Zentrum Berlin für Materialien und Energie (HZB) , Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
| | - Robert Seidel
- Institute of Methods for Material Development, Helmholtz-Zentrum Berlin für Materialien und Energie (HZB) , Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
| | - Bernd Winter
- Institute of Methods for Material Development, Helmholtz-Zentrum Berlin für Materialien und Energie (HZB) , Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
| | - Emad F Aziz
- Institute of Methods for Material Development, Helmholtz-Zentrum Berlin für Materialien und Energie (HZB) , Albert-Einstein-Strasse 15, D-12489 Berlin, Germany.,Department of Physics, Free University Berlin , Arnimallee 14, 14195 Berlin, Germany
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3
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Seidel R, Atak K, Thürmer S, Aziz EF, Winter B. Ti3+ Aqueous Solution: Hybridization and Electronic Relaxation Probed by State-Dependent Electron Spectroscopy. J Phys Chem B 2015. [DOI: 10.1021/acs.jpcb.5b03337] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Robert Seidel
- Institute
of Methods for Material Development, Helmholtz-Zentrum Berlin, Albert-Einstein-Strasse
15, D-12489 Berlin, Germany
| | - Kaan Atak
- Institute
of Methods for Material Development, Helmholtz-Zentrum Berlin, Albert-Einstein-Strasse
15, D-12489 Berlin, Germany
| | - Stephan Thürmer
- Department
of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502, Japan
| | - Emad F. Aziz
- Institute
of Methods for Material Development, Helmholtz-Zentrum Berlin, Albert-Einstein-Strasse
15, D-12489 Berlin, Germany
- Department
of Physics, Freie Universität Berlin, Arnimallee 14, D-14159 Berlin, Germany
| | - Bernd Winter
- Institute
of Methods for Material Development, Helmholtz-Zentrum Berlin, Albert-Einstein-Strasse
15, D-12489 Berlin, Germany
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