X-ray-absorption sum rules injj-coupled operators and ground-state moments of actinide ions

1996 ◽  
Vol 53 (21) ◽  
pp. 14458-14469 ◽  
Author(s):  
Gerrit van der Laan ◽  
B. T. Thole
Keyword(s):  
Ground State ◽  
Sum Rules ◽  
X Ray ◽  
X Ray Absorption ◽  
Actinide Ions

scholarly journals Revealing noncollinear magnetic ordering at the atomic scale via XMCD

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fridtjof Kielgast ◽  
Ivan Baev ◽  
Torben Beeck ◽  
Federico Pressacco ◽  
Michael Martins
Keyword(s):  
Ground State ◽  
Magnetic Circular Dichroism ◽  
Magnetic Moments ◽  
Magnetic Ordering ◽  
Atomic Scale ◽  
Angle Of Incidence ◽  
X Ray ◽  
First Time ◽  
X Ray Absorption ◽  
Magnetic Sublattices

AbstractMass-selected V and Fe monomers, as well as the heterodimer $${\text{Fe}}_1{\text{V}}_1$$ Fe 1 V 1 , were deposited on a Cu(001) surface. Their electronic and magnetic properties were investigated via X-ray absorption (XAS) and X-ray magnetic circular dichroism (XMCD) spectroscopy. Anisotropies in the magnetic moments of the deposited species could be examined by means of angle resolving XMCD, i.e. changing the X-ray angle of incidence. A weak adatom-substrate-coupling was found for both elements and, using group theoretical arguments, the ground state symmetries of the adatoms were determined. For the dimer, a switching from antiparallel to parallel orientation of the respective magnetic moments was observed. We show that this is due to the existence of a noncollinear spin-flop phase in the deposited dimers, which could be observed for the first time in such a small system. Making use of the two magnetic sublattices model, we were able to find the relative orientations for the dimer magnetic moments for different incidence angles.

Sum rules for polarization-dependent x-ray absorption

1995 ◽  
Vol 51 (2) ◽  
pp. 1282-1285 ◽  
Author(s):  
A. Ankudinov ◽  
J. J. Rehr
Keyword(s):  
Sum Rules ◽  
X Ray ◽  
X Ray Absorption

scholarly journals L-edge sum rule analysis on 3d transition metal sites: from d10to d0and towards application to extremely dilute metallo-enzymes

2018 ◽  
Vol 20 (12) ◽  
pp. 8166-8176 ◽  
Author(s):  
Hongxin Wang ◽  
Stephan Friedrich ◽  
Lei Li ◽  
Ziliang Mao ◽  
Pinghua Ge ◽  
...  
Keyword(s):  
Absorption Spectrum ◽  
Transition Metal ◽  
Metal Complex ◽  
Sum Rules ◽  
Sum Rule ◽  
X Ray ◽  
Metal Site ◽  
Integrated Intensity ◽  
Rule Analysis ◽  
X Ray Absorption

According to L-edge sum rules, the number of 3d vacancies at a transition metal site is directly proportional to the integrated intensity of the L-edge X-ray absorption spectrum (XAS) for the corresponding metal complex.

A single crystal, linearly polarized Fe 2p X-ray absorption study of gillespite

1998 ◽  
Vol 62 (1) ◽  
pp. 65-75 ◽  
Author(s):  
P. F. Schofield ◽  
G. van der Laan ◽  
C. M. B. Henderson ◽  
G. Cressey
Keyword(s):  
Single Crystal ◽  
Ground State ◽  
Branching Ratio ◽  
Linear Dichroism ◽  
Electronic Charge ◽  
Magic Angle ◽  
X Rays ◽  
X Ray ◽  
Peak Structure ◽  
X Ray Absorption

AbstractThe Fe 2p X-ray absorption spectra of single crystal gillespite, BaFeSi4O10, show a strong linear dichroism, i.e. a large difference in the absorption when measured with the polarization of the X-rays either parallel or perpendicular to the plane of the FeO4 group. The isotropic spectrum, obtained from measurement at the ‘magic angle’, and the polarization dependent spectra have been compared to atomic multiplet calculations and show an excellent agreement with theory. Analysis of the branching ratio, the linear dichroism, and the detailed peak structure confirms that the 5A1 level is the ground state at room temperature and pressure. The 5B2 level is sufficiently low in energy that a distortion of the electronic charge density, induced by increased pressure, may result in a 5B2 ground state.

CORE-HOLE EFFECT IN THE Ce L3 X-RAY ABSORPTION SPECTRA OF CeO2 AND CeFe2: NEW EXAMINATION BY USING RESONANT X-RAY EMISSION SPECTROSCOPY

2013 ◽  
Vol 27 (16) ◽  
pp. 1330012 ◽  
Author(s):  
A. KOTANI
Keyword(s):  
Absorption Spectra ◽  
Ground State ◽  
Theoretical Calculations ◽  
Emission Spectra ◽  
Core Hole ◽  
Final State ◽  
X Ray ◽  
The Core ◽  
X Ray Absorption ◽  
Hole Effect

We consider two different resonant X-ray emission spectra for Ce compounds: Ce 3d to 2p X-ray emission (denoted by 3d-RXES) and valence to 2p X-ray emission (v-RXES), both of which follow the Ce 2p to 5d resonant excitation. We propose that the comparison of the 3d- and v-RXES spectra is a new powerful method of directly detecting the core-hole effect in the final state of Ce L 3 X-ray absorption spectra (XAS). We applied this method to recent experimental RXES spectra for CeO 2 and CeFe 2, and showed unambiguously that the core-hole effect should be essential in the XAS of both materials. This result is confirmed by theoretical calculations, which reproduce well the experimental RXES and XAS spectra. We conclude that the ground state of CeO 2 is in the mixed state of 4f0 and [Formula: see text] configurations, where [Formula: see text] is a ligand hole, instead of a pure 4f0 configuration which was proposed recently by first-principles energy band calculations. Also, we conclude that the double peaks observed in L 3 XAS of CeFe 2 are caused by the 4f0 and 4f1 configurations, which are mixed in the ground state but separated in energy by the large core-hole potential in the final state of XAS.

Evolution of Ce-Valence in Ce-Rh-Si Compounds: Intermediate Valence in CeRh6Si4

2016 ◽  
Vol 257 ◽  
pp. 199-202
Author(s):  
Thomas Gruner ◽  
Christoph Geibel
Keyword(s):  
Ground State ◽  
Low Temperatures ◽  
Ternary Phase ◽  
Ternary Phase Diagram ◽  
Intermediate Valence ◽  
Characteristic Energy ◽  
X Ray ◽  
Resistivity Measurements ◽  
Intermediate Valent ◽  
X Ray Absorption

We synthesized polycrystalline samples of CeRh6Si4 and investigated its physical properties by means of magnetic susceptibility, specific heat and electrical resistivity measurements as well as LIII X-ray absorption spectroscopy. All results evidence an intermediate-valent (IV) Ce state with a valence close to 3.2 and a characteristic energy of about 300 K. Accordingly, we observe a Fermi liquid ground state at low temperatures with a slightly enhanced Sommerfeld coefficient γ = 28 mJ/molK2. Using presently available data on different compounds, we analyze the evolution of the Ce valence in the Ce-Rh-Si ternary phase diagram. The expected correlation with the distance to nearest Ce-ligands can be discerned. Thus, the evolution from a trivalent Ce3+ state in CeRh3Si2 to an IV state in CeRh6Si4 is related to a shortening of both the Ce-Rh and Ce-Si bonds in the first coordination sphere of Ce.

scholarly journals The Structure of Actinide Ions Exchanged into Native and Modified Zeolites and Clays

1999 ◽  
Vol 590 ◽  
Author(s):  
Stephen R. Wasserman ◽  
L. Soderholm ◽  
Daniel M. Giaquinta
Keyword(s):  
Pore Size ◽  
Organic Films ◽  
Mineral Surface ◽  
Hydrothermal Conditions ◽  
X Ray ◽  
Chemical Fate ◽  
Smectite Clays ◽  
Modified Zeolites ◽  
X Ray Absorption ◽  
Actinide Ions

ABSTRACTx-ray absorption spectroscopy (XAS) has been used to investigate the structure and valence of thorium (Th4+) and uranyl () cations exchanged into two classes of microporous aluminosilicate minerals: zeolites and smectite clays. XAS is also employed to examine the fate of the exchanged cations after modification of the mineral surface using self-assembled organic films and/or exposure to hydrothermal conditions. These treatments serve as models for the forces that ultimately determine the chemical fate of the actinide cations in the environment. The speciation of the cations depends on the pore size of the aluminosilicate, which is fixed for the zeolites and variable for the smectites.

Interpretation of x-ray absorption spectra by means of unoccupied orbitals of the ground state

1973 ◽  
Vol 14 (2) ◽  
pp. 234-238 ◽  
Author(s):  
L. N. Mazalov ◽  
A. P. Sadovskii ◽  
P. I. Vadash ◽  
F. G. Gel'mukhanov
Keyword(s):  
Absorption Spectra ◽  
Ground State ◽  
X Ray ◽  
X Ray Absorption
Sign in / Sign up

Export Citation Format

Share Document