Probing the Electronic Structure of Substituted Ferrocenes with High‐Resolution XANES Spectroscopy

Atkins, Andrew; Jacob, Christoph R.; Bauer, Matthias

doi:10.1002/chem.201200649

Cited by 44 publications

(83 citation statements)

References 57 publications

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“…[58] can lead to a spurious decrease of the oscillator strength in some cases. Previously, we found that this problem is even more severe in cases where the electric-dipole-electricdipole contribution to the oscillator strength is significantly smaller than the quadrupole oscillator strength [51]. However, if all second-order terms are included consistently the quadrupole oscillator strengths become origin-independent and no special placement of the origin is necessary.…”

Section: (µM) 0nmentioning

confidence: 96%

“…However, in vinylferrocene this symmetry is lost and the lowest-energy transition gains a small dipole oscillator strength (for a detailed discussion, see Ref. [51]). …”

Section: (µM) 0nmentioning

confidence: 99%

“…Usually, this is equivalent to placing the origin on the atom at which the excitation takes place. However, in cases where the dipole intensities are very small compared to the quadrupole intensities, this scheme sometimes places the origin far away from the excited core orbital [51], which seems unphysical and affects the resulting intensities significantly.…”

Section: Introductionmentioning

confidence: 99%

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

Bernadotte

Atkins

Jacob

2012

The Journal of Chemical Physics

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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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Section: (µM) 0nmentioning

confidence: 96%

“…However, in vinylferrocene this symmetry is lost and the lowest-energy transition gains a small dipole oscillator strength (for a detailed discussion, see Ref. [51]). …”

Section: (µM) 0nmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

Bernadotte

Atkins

Jacob

2012

The Journal of Chemical Physics

Self Cite

147

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show abstract

“…The ionization edge marks the onset of transitions into unbound continuum states, and the region of XAS spectra past the edge, the extended Xray absorption fine structure (EXAFS) region, can be interpreted using scattering theory [31]. Here, we will focus on the pre-edge region that provides unique information on the electronic structure by probing the low-lying unoccupied MOs [18].…”

Section: Interpretation Of Cu K-edge Xas Spectra: Copper Ammine Modelmentioning

confidence: 99%

“…Such a pronounced dependence of the energy splittings between peaks is due to the well-know limitations of TD-DFT in describing the energies of charge-transfer excitations [18,38] that could be overcome for the specific systems by employing rangeseparated hybrid functionals [39,40] or by carefully tuning the exact exchange admixture [38]. However, even though the exact position of these peaks might be unclear, an analysis of the underlying molecular orbital transitions is still possible [18].…”

Section: Calculated Xas Spectra For a Diverse Test Set Of Copper Compmentioning

confidence: 99%

Revisiting the Dependence of Cu K-Edge X-Ray Absorption Spectra on Oxidation State and Coordination Environment

Rudolph¹,

Jacob²

2018

Preprint

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X-ray absorption spectroscopy (XAS) at the Cu K-edge is an important tool for probing the properties of copper centers in transition metal chemistry and catalysis.However, the interpretation of experimental XAS spectra requires a detailed understanding of the dependence of spectroscopic features on the local geometric and electronic structure, which can be established by theoretical X-ray spectroscopy.Here, we present a systematic computational study of the Cu K-edge XAS spectra of selected Cu complexes based on time-dependent density-functional theory in combination with a molecular orbital analysis of the relevant transitions. For a series of Cu ammine model complexes as well as a comprehensive test set of 12 Cu(I) and 5 Cu(II) complexes, we revisit the dependence of the pre-edge region in Cu K-edge XAS spectra on oxidation state and coordination geometry. While our calculations confirm earlier experimental assignments, we can also reveal additional signatures of the ligand orbitals and identify the underlying orbital interactions.The comprehensive picture provided by this study will provide a reliable basis for the interpretation of in situ Cu K-edge XAS spectra of catalytic intermediates.2

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Technische Universität Kaiserslautern

2017

Geschichte Der Anorganischen Chemie

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Probing the Electronic Structure of Substituted Ferrocenes with High‐Resolution XANES Spectroscopy

Cited by 44 publications

References 57 publications

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

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

Revisiting the Dependence of Cu K-Edge X-Ray Absorption Spectra on Oxidation State and Coordination Environment

Technische Universität Kaiserslautern

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