X-ray-absorption near-edge structure of<i>3d</i>transition elements in tetrahedral coordination: The effect of bond-length variation

Bianconi, A.; Fritsch, E.; Calas, Georges; Petiau, J.

doi:10.1103/physrevb.32.4292

Cited by 162 publications

(110 citation statements)

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“…This phenomenon reflects the relation DE / 1/d 2 for a XANES resonance, in where DE denotes an energy difference of absorption feature relative to the ionization threshold and d represents the corresponding interatomic distance. 21 The observed features in the Ti K-edge near-edge spectra of FeTiO 3 at greater energy for E// ab and at smaller energy for E//c are then related to the smaller inter-atomic distance in the ab plane and the larger one in the c direction, respectively. Figure 4(a) shows the polarization-dependent Fe K-edge XANES spectra of FeTiO 3 .…”

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confidence: 93%

Orbital structure of FeTiO3 ilmenite investigated with polarization-dependent X-ray absorption spectroscopy and band structure calculations

Chen

Mei-Chun

Lin

et al. 2013

Applied Physics Letters

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confidence: 93%

Orbital structure of FeTiO3 ilmenite investigated with polarization-dependent X-ray absorption spectroscopy and band structure calculations

Chen

Mei-Chun

Lin

et al. 2013

Applied Physics Letters

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“…Reduction in peak intensity and an increased "white-line" at ∼5.488 keV compared to V 2 O 5 suggest a subtle change in the local electronic environment that may be due to variations in V-O interatomic distances, 26 or coordination environment. 27,28 The extended X-ray absorption fine structure (EXAFS), Fig. 2b showed a shift in the first V-O peak to a larger distance, and a contraction of the second shell V-V/V-O peak.…”

Section: Resultsmentioning

confidence: 99%

Communication—Sol-Gel Synthesized Magnesium Vanadium Oxide, Mg_xV₂O₅· nH₂O: The Role of Structural Mg²⁺on Battery Performance

Yin

Pelliccione

Lee

et al. 2016

J. Electrochem. Soc.

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Magnesium intercalated vanadium oxide xerogels, Mg 0.1 V 2 O 5 ·2.35H 2 O and Mg 0.2 V 2 O 5 ·2.46H 2 O were synthesized using an ion removal sol gel strategy. X-ray diffraction indicated lamellar ordering with turbostratic character. X-ray absorption spectroscopy indicated greater distortion of the vanadium-oxygen coordination environment in Mg In this report, Mg x V 2 O 5 ·nH 2 O were prepared by subtracting cations from a crystalline metal vanadate as an alternative strategy in order to adjust the cation amount, Figure 1a, different than the usual V 2 O 5 ·nH 2 O based sol-gel method.3 The as-prepared materials, x = 0.1 (MVO-1) and x = 0.2 (MVO-2), were characterized and electrochemical activity in lithium and magnesium electrolytes was determined. Post mortem analysis was done to determine the magnesium/vanadium ratio after cycling. Implications for use of Mg x V 2 O 5 ·nH 2 O in lithium and magnesium based batteries will be discussed, with particular focus on the structural role of Mg 2+ . ExperimentalSynthesis and characterization.-Mg x V 2 O 5 ·nH 2 O was synthesized via a sol gel process, 19 where aqueous magnesium vanadate (MgV 2 O 6 ) 20 was treated with an ion exchange resin. Characterization included X-ray diffraction (XRD), thermogravimetric analysis (TGA) and inductively-coupled plasma optical emission spectroscopy (ICP-OES).X-ray absorption spectroscopy (XAS) was acquired at the V Kedge (5.465 keV) in transmission mode at the National Synchrotron Light Source at Brookhaven National Laboratory. XAS scans of each sample and a V 2 O 5 reference were aligned to a vanadium foil measured simultaneously and merged in Athena, 21,22 and normalized utilizing AUTOBK. Theoretical FEFF6 23 models were created using orthorhombic V 2 O 5 crystal structure. 24 Distances are not corrected * Electrochemical Society Fellow. * * Electrochemical Society Member.z E-mail: esther.takeuchi@stonybrook.edu; kenneth.takeuchi.1@stonybrook.edu; amy.marschilok@stonybrook.edu for phase shifts, and are represented to be shorter than the actual interatomic distance.Electrochemical testing.-Working electrodes were prepared using Mg x V 2 O 5 ·nH 2 O, carbon and binder. The electrolytes were 1.0 M LiPF 6 in ethylene carbonate (EC)/dimethyl carbonate (DMC) (v/v 30/70) and 0.5 M magnesium bis(trifluoromethylsulfonylimide) (Mg(TFSI) 2 )/0.5 M dipropylene glycol dimethyl ether (dipro-glyme) in acetonitrile. Cyclic voltammetry (CV) was conducted for Li based system at 2.0 to 4.0 V with lithium auxiliary and reference electrodes with a scan rate of 0.1 mV/s. In Mg 2+ containing electrolyte Ag/AgNO 3 reference and carbon auxiliary were used with voltage limits of −1.0 and +0.85 V using a scan rate of 0.1 mV/s. Two electrode lithium cells were used for galvanostatic cycling between 2.0-3.8 V at rates of 0.1 C and 0.5 C, with 1C set as 200 mA/g. In magnesium based electrolyte a 0.1 C rate for both discharge and charge was used,

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“…52,53 The shoulder M 1 at 8.992 eV and the peak M 2 at 8.997 eV are assigned respectively to the 1s4pz and to the 1s 4px,y transitions. The broad peak B around 9 eV is caused by multiple scattering of the photoelectron within the first coordination shell of Cu II 54,55 so that its energy position indirectly depends upon the Cu II -N bond length. Long under debate, the assignment of peak S at 8.985 keV was eventually ascertained through polarization-resolved XAS experiments 56 and ab-initio calculations.…”

Section: Spectroscopic Characterizations Of Cumentioning

confidence: 99%

Elucidating the Ultrafast Dynamics of Photoinduced Charge Separation in Metalloporphyrin-Fullerene Dyads Across the Electromagnetic Spectrum

et al. 2016

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Metalloporphyrins are prominent building blocks in the synthetic toolbox of advanced photodriven molecular devices. When the central ion is paramagnetic, the relaxation pathways within the manifold of excited states are highly intricate so that unravelling the intramolecular energy and electron transfer processes is usually a very complex task. This fact is critically hampering the development of applications based on the enhanced coupling offered by the electronic exchange interaction. In this work, the dynamics of charge separation in a copper porphyrin-fullerene are studied with several complementary spectroscopic tools across the electromagnetic spectrum (from near infra-red to X-ray wavelengths), each of them providing specific diagnostics. Correlating the various rates clearly demonstrates that the lifetime of the photoinduced charge-separated state exceeds by about 10 fold that of the isolated photoexcited Cu II porphyrin. As revealed by the spectral modifications in the XANES region, this stabilization is accompanied by a transient change in covalency around the Cu II center, which is induced by an enhanced interaction with the C 60 moiety. This experimental finding is further confirmed by state-of-the art calculations using DFT and TD-DFT including dispersion effects that explain the electrostatic and structural origins of this interaction, as the Cu II P cation becomes ruffled and approaches closer to the fullerene in the charge-separated state. From a methodological point of view, these results exemplify the potential of multielectron excitation features in transient X-ray spectra as future diagnostics of sub-femtosecond electronic dynamics. From a practical point of view, this work is paving the way for elucidating out-ofequilibrium electron transfer events coupled to magnetic interaction processes on their intrinsic time-scales.

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X-ray-absorption near-edge structure of3dtransition elements in tetrahedral coordination: The effect of bond-length variation

Cited by 162 publications

References 7 publications

Orbital structure of FeTiO3 ilmenite investigated with polarization-dependent X-ray absorption spectroscopy and band structure calculations

Orbital structure of FeTiO3 ilmenite investigated with polarization-dependent X-ray absorption spectroscopy and band structure calculations

Communication—Sol-Gel Synthesized Magnesium Vanadium Oxide, Mg_xV₂O₅· nH₂O: The Role of Structural Mg²⁺on Battery Performance

Elucidating the Ultrafast Dynamics of Photoinduced Charge Separation in Metalloporphyrin-Fullerene Dyads Across the Electromagnetic Spectrum

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X-ray-absorption near-edge structure of3dtransition elements in tetrahedral coordination: The effect of bond-length variation

Cited by 162 publications

References 7 publications

Orbital structure of FeTiO3 ilmenite investigated with polarization-dependent X-ray absorption spectroscopy and band structure calculations

Orbital structure of FeTiO3 ilmenite investigated with polarization-dependent X-ray absorption spectroscopy and band structure calculations

Communication—Sol-Gel Synthesized Magnesium Vanadium Oxide, MgxV2O5· nH2O: The Role of Structural Mg2+on Battery Performance

Elucidating the Ultrafast Dynamics of Photoinduced Charge Separation in Metalloporphyrin-Fullerene Dyads Across the Electromagnetic Spectrum

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Communication—Sol-Gel Synthesized Magnesium Vanadium Oxide, Mg_xV₂O₅· nH₂O: The Role of Structural Mg²⁺on Battery Performance