X‐ray Absorption and Emission Spectroscopy

Glatzel, Pieter; Juhin, Amélie

doi:10.1002/9781118681909.ch2

Cited by 8 publications

(8 citation statements)

References 130 publications

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“…The more intense and lower in energy so-called Kβ mainline spectra (Figure 5, top left) arise from the fluorescence occurring after Fe 3p electrons refill the Fe 1s core-hole. 70 Due to the 3p–3d exchange, this feature is split into two peaks: the Kβ 1,3 and Kβ′. To higher energy, the so-called VtC XES (Figure 5, top right) features arise from transitions from filled ligand n p/ n s orbitals to the metal 1s core-hole (Kβ 2,5 /Kβ″ features), which gain intensity though Fe n p mixing into filled valence orbitals.…”

Section: Resultsmentioning

confidence: 99%

X-ray Absorption and Emission Spectroscopic Studies of [L₂Fe₂S₂]ⁿ Model Complexes: Implications for the Experimental Evaluation of Redox States in Iron–Sulfur Clusters

et al. 2016

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Herein, a systematic study of [L2Fe2S2]n model complexes (where L = bis(benzimidazolato) and n = 2-, 3-, 4-) has been carried out using iron and sulfur K-edge X-ray absorption (XAS) and iron Kβ and valence-to-core X-ray emission spectroscopies (XES). These data are used as a test set to evaluate the relative strengths and weaknesses of X-ray core level spectroscopies in assessing redox changes in iron–sulfur clusters. The results are correlated to density functional theory (DFT) calculations of the spectra in order to further support the quantitative information that can be extracted from the experimental data. It is demonstrated that due to canceling effects of covalency and spin state, the information that can be extracted from Fe Kβ XES mainlines is limited. However, a careful analysis of the Fe K-edge XAS data shows that localized valence vs delocalized valence species may be differentiated on the basis of the pre-edge and K-edge energies. These findings are then applied to existing literature Fe K-edge XAS data on the iron protein, P-cluster, and FeMoco sites of nitrogenase. The ability to assess the extent of delocalization in the iron protein vs the P-cluster is highlighted. In addition, possible charge states for FeMoco on the basis of Fe K-edge XAS data are discussed. This study provides an important reference for future X-ray spectroscopic studies of iron–sulfur clusters.

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Section: Resultsmentioning

confidence: 99%

X-ray Absorption and Emission Spectroscopic Studies of [L₂Fe₂S₂]ⁿ Model Complexes: Implications for the Experimental Evaluation of Redox States in Iron–Sulfur Clusters

et al. 2016

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“…Using an emission spectrometer with energy resolution below the initial core-hole broadening, spectra with subnatural lifetime resolution can be recorded. The technique of reducing the apparent core-hole lifetime broadening is referred as high energy resolution fluorescence detected (HERFD) XAS and has first been suggested by Hämäläinen et al It corresponds to a horizontal cut through a RIXS plane presented in Figure at fixed emission energy at the top of the fluorescence line. In the case of sulfur, the 1s core-hole broadening is only 0.522 eV, which practically equals our overall (monochromator and spectrometer) experimental resolution of ∼0.55 eV, so at first glance no significant narrowing effect could be expected in this case.…”

Section: Results and Discussionmentioning

confidence: 99%

Operando Resonant Inelastic X-ray Scattering: An Appropriate Tool to Characterize Sulfur in Li–S Batteries

et al. 2016

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Application of new analytical tools providing insight into the mechanism of lithium−polysulfide formation in the cathode and their interaction with the host matrix and electrolyte is essential for further development of Li−S batteries. In this work, resonant inelastic X-ray scattering (RIXS) measurements at the sulfur K-edge were performed on the Li−S battery in operando mode to study the lithium-polysulfide formation during the discharge process. The relative amounts of each sulfur compound in the cathode during the discharge process were determined from the linear combination fit using reference spectra measured on standard sulfur compounds. Because of resonant excitation condition the sensitivity for the lithium−polysulfide detection was significantly enhanced, while the sulfate signal from the electrolyte was heavily suppressed. In addition, the influence of self-absorption effects in the analysis was minimized due to fixed excitation energy. Consequently, a full quantitative analysis could be performed for the conventional Li−S battery consisting of sulfur−carbon composite cathode free from any additives and a LiTFSI based electrolyte.

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“…Non resonant XES consists of scanning the emitted fluorescence with a CAS at a fixed incoming X‐ray energy, above an absorption edge. X‐ray emission spectroscopy also permits probing the local electronic structure of the absorbing element and has been used extensively (Bergmann and Glatzel, 2009; Glatzel and Juhin, 2013). With respect to XANES, XES probes occupied valence electrons (directly or indirectly) and is more sensitive to the local charge density.…”

Section: Methodsmentioning

confidence: 99%

High‐Energy Resolution Fluorescence Detected X‐Ray Absorption Spectroscopy: A Powerful New Structural Tool in Environmental Biogeochemistry Sciences

et al. 2017

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The study of the speciation of highly diluted elements by X-ray absorption spectroscopy (XAS) is extremely challenging, especially in environmental biogeochemistry sciences. Here we present an innovative synchrotron spectroscopy technique: high-energy resolution fluorescence detected XAS (HERFD-XAS). With this approach, measurement of the XAS signal in fluorescence mode using a crystal analyzer spectrometer with a ∼1-eV energy resolution helps to overcome restrictions on sample concentrations that can be typically measured with a solid-state detector. We briefly describe the method, from both an instrumental and spectroscopic point of view, and emphasize the effects of energy resolution on the XAS measurements. We then illustrate the positive impact of this technique in terms of detection limit with two examples dealing with Ce in ecologically relevant organisms and with Hg species in natural environments. The sharp and well-marked features of the HERFD-X-ray absorption near-edge structure spectra obtained enable us to determine unambiguously and with greater precision the speciation of the probed elements. This is a major technological advance, with strong benefits for the study of highly diluted elements using XAS. It also opens new possibilities to explore the speciation of a target chemical element at natural concentration levels, which is critical in the fields of environmental and biogeochemistry sciences.

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X‐ray Absorption and Emission Spectroscopy

Cited by 8 publications

References 130 publications

X-ray Absorption and Emission Spectroscopic Studies of [L₂Fe₂S₂]ⁿ Model Complexes: Implications for the Experimental Evaluation of Redox States in Iron–Sulfur Clusters

X-ray Absorption and Emission Spectroscopic Studies of [L₂Fe₂S₂]ⁿ Model Complexes: Implications for the Experimental Evaluation of Redox States in Iron–Sulfur Clusters

Operando Resonant Inelastic X-ray Scattering: An Appropriate Tool to Characterize Sulfur in Li–S Batteries

High‐Energy Resolution Fluorescence Detected X‐Ray Absorption Spectroscopy: A Powerful New Structural Tool in Environmental Biogeochemistry Sciences

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X‐ray Absorption and Emission Spectroscopy

Cited by 8 publications

References 130 publications

X-ray Absorption and Emission Spectroscopic Studies of [L2Fe2S2]n Model Complexes: Implications for the Experimental Evaluation of Redox States in Iron–Sulfur Clusters

X-ray Absorption and Emission Spectroscopic Studies of [L2Fe2S2]n Model Complexes: Implications for the Experimental Evaluation of Redox States in Iron–Sulfur Clusters

Operando Resonant Inelastic X-ray Scattering: An Appropriate Tool to Characterize Sulfur in Li–S Batteries

High‐Energy Resolution Fluorescence Detected X‐Ray Absorption Spectroscopy: A Powerful New Structural Tool in Environmental Biogeochemistry Sciences

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X-ray Absorption and Emission Spectroscopic Studies of [L₂Fe₂S₂]ⁿ Model Complexes: Implications for the Experimental Evaluation of Redox States in Iron–Sulfur Clusters

X-ray Absorption and Emission Spectroscopic Studies of [L₂Fe₂S₂]ⁿ Model Complexes: Implications for the Experimental Evaluation of Redox States in Iron–Sulfur Clusters