Electronic Structure of Third-Row Elements in Different Local Symmetries Studied by Valence-to-Core X-ray Emission Spectroscopy

Petrič, M.; Bohinc, R.; Bučar, K.; Nowak, S.; Žitnik, M.; Kavčič, M.

doi:10.1021/acs.inorgchem.6b00237

Cited by 19 publications

(20 citation statements)

References 51 publications

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“…The last several years have seen growing interest in X-ray emission spectroscopy (XES), and especially valence-to-core XES, − as an important complement to XANES. In the context of sulfur, the synchrotron-based study of Alonso Mori et al for inorganic compounds and the older laboratory-based work of Yasuda and Kakiyama for organic compounds show a considerable richness of spectral features and sensitivity to chemically relevant information.…”

Section: Introductionmentioning

confidence: 99%

Probing Sulfur Chemical and Electronic Structure with Experimental Observation and Quantitative Theoretical Prediction of Kα and Valence-to-Core Kβ X-ray Emission Spectroscopy

et al. 2020

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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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Section: Introductionmentioning

confidence: 99%

Probing Sulfur Chemical and Electronic Structure with Experimental Observation and Quantitative Theoretical Prediction of Kα and Valence-to-Core Kβ X-ray Emission Spectroscopy

et al. 2020

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“…[3][4][5][6][7][8] Despite excellent analytical capabilities of XAS, the limited access to synchrotron beamlines represents a bottleneck for more routine analysis. Alternatively, complementary element specific information of sulfur local electronic structure can be obtained using X-ray emission spectroscopy (XES), [9][10][11][12] which can be successfully performed also in a smaller lab employing laboratory excitation sources. However, due to specific tender X-ray range, sulfur XES requires dedicated in-vacuum emission spectrometers being introduced only very recently.…”

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Sulfur valence-to-core X-ray emission spectroscopy study of lithium sulfur batteries

et al. 2021

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“…14 The potential of using VtC XES to study the geometrical structure of molecules containing 3rd row elements (P, S, Cl) in different local symmetries was recently demonstrated. 15,16 If it is a big challenge to develop tools to locate aluminum in the zeolite, it is even more challenging to synthesize the zeolite with aluminum in specific T positions. The sitting and distribution of aluminum inside the zeolite framework are, however, not random.…”

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confidence: 99%

Distribution of aluminum over different T-sites in ferrierite zeolites studied with aluminum valence to core X-ray emission spectroscopy

Bohinc

Hoszowska

Dousse

et al. 2017

Phys. Chem. Chem. Phys.

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The potential of valence to core Al X-ray emission spectroscopy to determine aluminum distribution in ferrierite zeolites was investigated. The recorded emission spectra of four samples prepared with different structure directing agents exhibit slight variations in the position of the main emission peak and the intensity of its low energy shoulder. Theoretical calculations indicate that an increased intensity of the Kb x shoulder in the Al emission spectra can be linked to a predominant occupation of the T3 site by a single aluminum atom. This study thus suggests that valence to core X-ray emission spectroscopy can be applied to help determine the occupation of aluminum at crystallographic T-sites in zeolites.Zeolites are microporous crystalline aluminosilicates whose frameworks are composed of corner sharing TO 4 tetrahedra (T = either silicon or aluminum). The mutual arrangement of these subunits defines the framework structure which is characterized by periodical pores and channels. Replacing silicon atoms with aluminum atoms at the T-sites introduces a local negative charge to the framework which can be stabilized by protons or cations, which confer the catalytic activity to the zeolite. The catalytic activity is therefore directly related to the positioning of aluminum atoms within the zeolite framework.The determination of both the location of aluminum atoms at individual T-sites (aluminum sitting) and the mutual arrangement of several aluminum atoms (aluminum distribution) remains an open question in zeolite structural analysis.1 The Magic Angle Spinning-Nuclear Magnetic Resonance (MAS-NMR) spectroscopy of 29Si represents a standard method to address the Si-Al connectivity, however, not providing information about the absolute position of aluminum and silicon atoms inside the framework.27 Al MAS NMR is sensitive to the averaged Al-O-Si angle and therefore partially yields aluminum occupation. sequences, where at least one aluminum atom is located in the second coordination shell of another aluminum atom, has been determined. Due to a large penetration depth of X-rays, X-ray-based techniques are suited for the characterization of catalysts under reaction conditions. X-ray absorption fine structure (EXAFS) analysis combined with DFT simulations showed a preference of aluminum for the T sites in the 4-ring of zeolite beta. 7 X-ray absorption near-edge structure spectroscopy (XANES) was successfully applied to monitor aluminum coordination as a function of temperature and gas composition. 8 X-ray diffraction (XRD) techniques are, in general, not suitable for distinguishing silicon and aluminum atoms because of their similar scattering power. The structural changes induced by introducing aluminum, mainly an elongation of the T-O distance by ca. 0.1 Å, can in some cases indicate the position of aluminum. 9 However, this difference is obscured by the low Al/Si proportion at that specific T-site. Using the X-ray standing waves, the location of aluminum in scolecite (NAT framework type) has been determined. 10 Alt...

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Electronic Structure of Third-Row Elements in Different Local Symmetries Studied by Valence-to-Core X-ray Emission Spectroscopy

Cited by 19 publications

References 51 publications

Probing Sulfur Chemical and Electronic Structure with Experimental Observation and Quantitative Theoretical Prediction of Kα and Valence-to-Core Kβ X-ray Emission Spectroscopy

Probing Sulfur Chemical and Electronic Structure with Experimental Observation and Quantitative Theoretical Prediction of Kα and Valence-to-Core Kβ X-ray Emission Spectroscopy

Sulfur valence-to-core X-ray emission spectroscopy study of lithium sulfur batteries

Distribution of aluminum over different T-sites in ferrierite zeolites studied with aluminum valence to core X-ray emission spectroscopy

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