109 research outputs found
Theoretical study of resonant x-ray emission spectroscopy of Mn films on Ag
We report a theoretical study on resonant x-ray emission spectra (RXES) in
the whole energy region of the Mn white lines for three prototypical
Mn/Ag(001) systems: (i) a Mn impurity in Ag, (ii) an adsorbed Mn monolayer on
Ag, and (iii) a thick Mn film. The calculated RXES spectra depend strongly on
the excitation energy. At excitation, the spectra of all three systems
are dominated by the elastic peak. For excitation energies around , and
between and , however, most of the spectral weight comes from
inelastic x-ray scattering. The line shape of these inelastic ``satellite''
structures changes considerably between the three considered Mn/Ag systems, a
fact that may be attributed to changes in the bonding nature of the Mn-
orbitals. The system-dependence of the RXES spectrum is thus found to be much
stronger than that of the corresponding absorption spectrum. Our results
suggest that RXES in the Mn region may be used as a sensitive probe
of the local environment of Mn atoms.Comment: 9 pages, 11 figure
Electronic structure investigation of CoO by means of soft X-ray scattering
The electronic structure of CoO is studied by resonant inelastic soft X-ray
scattering spectroscopy using photon energies across the Co 2p absorption
edges. The different spectral contributions from the energy-loss structures are
identified as Raman scattering due to d-d and charge-transfer excitations. For
excitation energies close to the L3 resonance, the spectral features are
dominated by quartet-quartet and quartet-doublet transitions of the 3d7
configuration. At excitation energies corresponding to the satellites in the Co
2p X-ray absorption spectrum of CoO, the emission features are instead
dominated by charge-transfer transitions to the 3d8L-1 final state. The spectra
are interpreted and discussed with the support of simulations within the single
impurity Anderson model with full multiplet effects which are found to yield
consistent spectral functions to the experimental data.Comment: 8 pages, 2 figures, 2 tables,
http://link.aps.org/doi/10.1103/PhysRevB.65.20510
Large magnetic circular dichroism in resonant inelastic x-ray scattering at the Mn L-edge of Mn-Zn ferrite
We report resonant inelastic x-ray scattering (RIXS) excited by circularly
polarized x-rays on Mn-Zn ferrite at the Mn L2,3-resonances. We demonstrate
that crystal field excitations, as expected for localized systems, dominate the
RIXS spectra and thus their dichroic asymmetry cannot be interpreted in terms
of spin-resolved partial density of states, which has been the standard
approach for RIXS dichroism. We observe large dichroic RIXS at the L2-resonance
which we attribute to the absence of metallic core hole screening in the
insulating Mn-ferrite. On the other hand, reduced L3-RIXS dichroism is
interpreted as an effect of longer scattering time that enables spin-lattice
core hole relaxation via magnons and phonons occurring on a femtosecond time
scale.Comment: 7 pages, 2 figures,
http://link.aps.org/doi/10.1103/PhysRevB.74.17240
Insights into the Electronic Structure of a U(IV) Amido and U(V) Imido Complex
Reaction of the N-heterocylic carbene ligand PrIm (L) and lithium bis(trimethylsilyl)amide (TMSA) as a base with UCl resulted in U(IV) and U(V) complexes. Uranium\u27s +V oxidation state in (HL)[U(V)(TMSI)Cl] (TMSI=trimethylsilylimido) (2) was confirmed by HERFD-XANES measurements. Solid state characterization by SC-XRD and geometry optimisation of [U(IV)(L)(TMSA)Cl] (1) indicated a silylamido ligand mediated inverse trans influence (ITI). The ITI was examined regarding different metal oxidation states and was compared to transition metal analogues by theoretical calculations
The electronic structure of polyaniline and doped phases studied by soft X-ray absorption and emission spectroscopies
The electronic structure of the conjugated polymer, polyaniline, has been
studied by resonant and nonresonant X-ray emission spectroscopy using
synchrotron radiation for the excitation. The measurements were made on
polyaniline and a few doped (protonated) phases for both the carbon and
nitrogen contents. The resonant X-ray emission spectra show depletion of the
{\pi} electron bands due to the selective excitation which enhances the effect
of symmetry selection rules. The valence band structures in the X-ray emission
spectra attributed to the {\pi} bands show unambiguous changes of the
electronic structure upon protonation. By comparing to X-ray absorption
measurements, the chemical bonding and electronic configuration is
characterized.Comment: 8 pages, 8 pictures,
http://jcp.aip.org/resource/1/jcpsa6/v111/i10/p4756_s
Resonant soft X-ray Raman scattering of NiO
Resonant soft X-ray Raman scattering measurements on NiO have been made at
photon energies across the Ni 2p absorption edges. The details of the spectral
features are identified as Raman scattering due to d-d and charge-transfer
excitations. The spectra are interpreted within the single impurity Anderson
model, including multiplets, crystal-field and charge-transfer effects. At
threshold excitation, the spectral features consists of triplet-triplet and
triplet-singlet transitions of the 3d8 configuration. For excitation energies
corresponding to the charge-transfer region in the Ni 2p X-ray absorption
spectrum of NiO, the emission spectra are instead dominated by charge-transfer
transitions to the 3d9L-1 final state. Comparisons of the final states with
other spectroscopical techniques are also made.Comment: 9 pages, 2 figures, 2 tables,
http://iopscience.iop.org/0953-8984/14/13/32
Momentum Dependence of Resonant Inelastic X-Ray Scattering Spectrum in Insulating Cuprates
The resonant inelastic x-ray scattering spectrum in insulating cuprates is
examined by using the exact diagonalization technique on small clusters in the
two-dimensional Hubbard model with second and third neighbor hopping terms.
When the incident photon energy is tuned near the Cu K absorption edges, we
find that the features of the unoccupied upper Hubbard band can be extracted
from the spectrum through an anisotropic momentum dependence. They provide an
opportunity for the understanding of the different behavior of hole- and
electron-doped superconductors.Comment: 4 pages with 4 figures, to be published in PR
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