Na K-XANES and EXAFS studies in sodium halides

Murata, Takatoshi; Matsukawa, T.; Naoé, Shun-ichi

doi:10.1016/0921-4526(89)90407-9

Cited by 10 publications

(3 citation statements)

References 3 publications

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“…The Na-Cl distance is 2.61 Å in Fig. 4, which is close to the result of Murata et al 9,10 (2.5 Å), who measured genuine EXAFS spectra using the ultra-high-vacuum soft X-ray beam line at the Institute for Molecular Science. The Na-Cl distance has been reported to be 2.82 Å.…”

Section: Resultssupporting

confidence: 88%

Extended X-ray emission fine structure of sodium†

Kawai¹,

Hayashi²,

Tanuma³

1998

Analyst

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Sodium X-ray emission spectra of NaCl powder were measured by wavelength-dispersive X-ray fluorescence spectrometry and electron probe microanalysis. The X-ray emission spectra show an oscillating fine structure similar to that of the extended X-ray absorption fine structure (EXAFS). The Fourier transform of the X-ray fluorescence spectrum shows a similar radial distribution of atoms around the sodium. These findings demonstrate that a wavelength-dispersive X-ray emission spectrometer is a powerful tool for analyzing the local structure around a light element in condensed matter, which is still not an easy task with using a third-generation synchrotron radiation facility.

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Section: Resultssupporting

confidence: 88%

Extended X-ray emission fine structure of sodium†

Kawai¹,

Hayashi²,

Tanuma³

1998

Analyst

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“…Apart from a slight broadening for sample 3 the spectra are very similar. Na K edge XANES spectra have been measured in halides, minerals, and glasses, but none are similar to spectra measured on our samples. To the best of our knowledge, there are no reports of spectra on perovskites containing high-Z elements such as Ba and Os.…”

Section: Resultsmentioning

confidence: 47%

Doping Evolution of the Local Electronic and Structural Properties of the Double Perovskite Ba₂Na_1–xCa_xOsO₆

et al. 2020

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We present a combined experimental and computational study of the effect of charge doping in the osmium based double perovskite Ba 2 Na 1– x Ca x OsO 6 for 0 ≤ x ≤ 1 in order to provide a structural and electronic basis for understanding this complex Dirac–Mott insulator material. Specifically, we investigate the effects of the substitution of monovalent Na with divalent Ca, a form of charge doping or alloying that nominally tunes the system from Os 7+ with a 5d 1 configuration to Os 6+ with 5d 2 configuration. After an X-ray diffraction characterization, the local atomic and electronic structure has been experimentally probed by X-ray absorption fine structure at all the cation absorption edges at room temperature; the simulations have been performed using ab initio density functional methods. We find that the substitution of Na by Ca induces a linear volume expansion of the crystal structure which indicates an effective alloying due to the substitution process in the whole doping range. The local structure corresponds to the expected double perovskite one with rock-salt arrangement of Na/Ca in the B site and Os in the B′ one for all the compositions. X-ray absorption near edge structure measurements show a smooth decrease of the oxidation state of Os from 7+ (5d 1 ) to 6+ (5d 2 ) with increasing Ca concentration, while the oxidation states of Ba, Na, and Ca are constant. This indicates that the substitution of Na by Ca gives rise to an effective electron transfer from the B to the B′ site. The comparison between X-ray absorption measurements and ab initio simulations reveals that the expansion of the Os–O bond length induces a reduction of the crystal field splitting of unoccupied Os derived d states.

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“…Recently, x-ray absorption spectroscopy has become a powerful tool for the study of electronic energy bands and local crystal structures of ionic compounds [1]. Previous analyses of the x-ray absorption near-edge structures (XANESs) in NaCl-type alkali halides have been performed [2][3][4][5], but the most interesting results have been obtained while studying the phase transition in ionic compounds associated with both XANES [6][7][8] and EXAFS [9] regions. Recently, in a series of studies, the analysis of AgBr, KBr, NaBr and RbCl electronic structures using joint experimental and theoretical XANES studies have been made [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Electronic structure of RbBr during the phase transition: x-ray absorption near-edge structure analysis

Soldatov

Ingalls

1996

J. Phys.: Condens. Matter

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The x-ray absorption near-edge structure (XANES) at the Br and Rb K edges in the low-pressure (B1) and the high-pressure phase (B2) of RbBr has been analysed. We have used a full multiple-scattering method to investigate the structure of the RbBr conduction band. Theoretical K-edge absorption spectra obtained over a large energy interval were used to analyse the experimental data. The XANES is found to be determined by the multiple scattering of the photoelectron in a large cluster (30 or more atoms). For an energy interval up to 50 eV above the main edge, the single-scattering approximation is found to be less satisfactory. Comparative analysis of the XANES of the two different crystal phases makes it possible to examine the role of local symmetry and the characteristics of neighbouring atoms around the absorbing site as well as the conduction band of RbBr.

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Na K-XANES and EXAFS studies in sodium halides

Cited by 10 publications

References 3 publications

Extended X-ray emission fine structure of sodium†

Extended X-ray emission fine structure of sodium†

Doping Evolution of the Local Electronic and Structural Properties of the Double Perovskite Ba₂Na_1–xCa_xOsO₆

Electronic structure of RbBr during the phase transition: x-ray absorption near-edge structure analysis

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Na K-XANES and EXAFS studies in sodium halides

Cited by 10 publications

References 3 publications

Extended X-ray emission fine structure of sodium†

Extended X-ray emission fine structure of sodium†

Doping Evolution of the Local Electronic and Structural Properties of the Double Perovskite Ba2Na1–xCaxOsO6

Electronic structure of RbBr during the phase transition: x-ray absorption near-edge structure analysis

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Doping Evolution of the Local Electronic and Structural Properties of the Double Perovskite Ba₂Na_1–xCa_xOsO₆