Valence-to-Core X-ray Emission Spectroscopy: A Sensitive Probe of the Nature of a Bound Ligand

Pollock, Christopher J.; DeBeer, Serena

doi:10.1021/ja200560z

Cited by 132 publications

(212 citation statements)

References 37 publications

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“…The integration times are 20 s for the main K energy range and 80 s for the valence region. The data cleanly demonstrate all expected features over the entire energy range, including the weak peak due to electron transfer from a ligand semicore shell to the 1s core hole on the Co. 5,104 We emphasize that no background subtraction has been performed. All stray scatter, shielding fluorescence, harmonic signals from the SBCA, and other backgrounds are efficiently rejected by choosing a ~300-eV wide acceptance window on the SDD.…”

Section: Ivb Laboratory Nonresonant Xesmentioning

confidence: 52%

A laboratory-based hard x-ray monochromator for high-resolution x-ray emission spectroscopy and x-ray absorption near edge structure measurements

Seidler

Mortensen

Remesnik

et al. 2014

Review of Scientific Instruments

144

160

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We report the development of a laboratory-based Rowland-circle monochromator that incorporates a low power x-ray (bremsstrahlung) tube source, a spherically-bent crystal analyzer (SBCA), and an energy-resolving solid-state detector. This relatively inexpensive, introductory level instrument achieves 1-eV energy resolution for photon energies of ~5 keV to ~10 keV while also demonstrating a net efficiency previously seen only in laboratory monochromators having much coarser energy resolution. Despite the use of only a compact, air-cooled 10 W xray tube, we find count rates for nonresonant x-ray emission spectroscopy (XES) comparable to those achieved at monochromatized spectroscopy beamlines at synchrotron light sources. For xray absorption near edge structure (XANES), the monochromatized flux is small (due to the use of a low-powered x-ray generator) but still useful for routine transmission-mode studies of concentrated samples. These results indicate that upgrading to a standard commercial highpower line-focused x-ray tube or rotating anode x-ray generator would result in monochromatized fluxes of order 10 6 -10 7 photons/s with no loss in energy resolution. This work establishes core technical capabilities for a rejuvenation of laboratory-based hard x-ray spectroscopies that could have special relevance for contemporary research on catalytic or electrical energy storage systems using transition-metal, lanthanide or noble-metal active species.

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Section: Ivb Laboratory Nonresonant Xesmentioning

confidence: 52%

A laboratory-based hard x-ray monochromator for high-resolution x-ray emission spectroscopy and x-ray absorption near edge structure measurements

Seidler

Mortensen

Remesnik

et al. 2014

Review of Scientific Instruments

144

160

View full text Add to dashboard Cite

show abstract

“…[35] Promising advances in TDDFT or DFT/CI-based (CI, configuration interaction) approaches have been made towards the calculation of various X-ray absorption and emission features relevant for iron complexes, [36,37,38,39] again with the potential of structural assigment or electronic structure calibration. [40,41] Nuclear resonance vibrational spectroscopy (NRVS), selectively probing the iron-containing vibrational modes using nuclear excitations with synchrotron radiation, has lately become an important tool in the bioinorganic chemistry of iron systems.…”

Section: Density Functional Theory Calculations Of Spectroscopic Propmentioning

confidence: 99%

Mono- and binuclear non-heme iron chemistry from a theoretical perspective

et al. 2016

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In this minireview, we provide an account of the current state-of-the-art developments in the area of mono-and binuclear non-heme enzymes (NHFe and NHFe2) and the smaller NHFe(2) synthetic models, mostly from a theoretical and computational perspective. The sheer complexity, and at the same time the beauty, of the NHFe(2) world represent a challenge for both experimental as well as theoretical methods. We emphasize that the concerted progress on both theoretical and experimental side is a conditio sine qua non for future understanding, exploration and utilization of the NHFe(2) systems.After briefly discussing the current challenges and advances in the computational methodology, we review the recent spectroscopic and computational studies of NHFe(2) enzymatic and inorganic systems and highlight the correlations between various experimental data (spectroscopic, kinetic, thermodynamic, electrochemical) and computations. Throughout, we attempt to keep in mind the most fascinating and attractive phenomenon in the NHFe(2) chemistry which is the fact that despite the strong oxidative power of many reactive intermediates, the NHFe(2) enzymes perform catalysis with high selectivity. We conclude with our personal viewpoint and hope that further developments in quantum chemistry and especially in the field of multireference wave function methods are needed to have a solid theoretical basis for the NHFe(2) studies, mostly by providing benchmarking and calibration of the computationally efficient and easy-to-use DFT methods.

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“…X-ray spectroscopy [1][2][3] is a powerful spectroscopic tool for the elucidation of structural and electronic properties of materials [4][5][6] and (bio-)molecular systems [7][8][9]. X-ray absorption spectroscopy (XAS) probes the excitation of core electrons.…”

Section: Introductionmentioning

confidence: 99%

Origin-independent calculation of quadrupole intensities in X-ray spectroscopy

Bernadotte

Atkins

Jacob

2012

The Journal of Chemical Physics

147

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For electronic excitations in the ultraviolet and visible range of the electromagnetic spectrum, the intensities are usually calculated within the dipole approximation, which assumes that the oscillating electric field is constant over the length scale of the transition. For the short wavelengths used in hard X-ray spectroscopy, the dipole approximation may not be adequate. In particular, for metal K-edge X-ray absorption spectroscopy (XAS), it becomes necessary to include higher-order contributions. In quantum-chemical approaches to X-ray spectroscopy, these socalled quadrupole intensities have so far been calculated by including contributions depending on the square of the electric-quadrupole and magnetic-dipole transition moments. However, the resulting quadrupole intensities depend on the choice of the origin of the coordinate system. Here, we show that for obtaining an originindependent theory, one has to include all contributions that are of the same order in the wave vector consistently. This leads to two additional contributions depending on products of the electric-dipole andelectric-octupole and of the electric-dipole and magnetic-quadrupole transition moments, respectively. We have implemented such an origin-independent calculation of quadrupole intensities in XAS within timedependent density-functional theory, and demonstrate its usefulness for the calculation of metal and ligand K-edge XAS spectra of transition metal complexes.2

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Valence-to-Core X-ray Emission Spectroscopy: A Sensitive Probe of the Nature of a Bound Ligand

Cited by 132 publications

References 37 publications

A laboratory-based hard x-ray monochromator for high-resolution x-ray emission spectroscopy and x-ray absorption near edge structure measurements

A laboratory-based hard x-ray monochromator for high-resolution x-ray emission spectroscopy and x-ray absorption near edge structure measurements

Mono- and binuclear non-heme iron chemistry from a theoretical perspective

Origin-independent calculation of quadrupole intensities in X-ray spectroscopy

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