Near-edge x-ray-absorption fine structure in uranium compounds
For a number of metallic and nonmetallic U systems as well as a few Th compounds, the near-edge x-ray-absorption fine-structure spectra, taken by transmission and total-electron-yield techniques, are reported at the L/sub 3/, M/sub 3/, M/sub 4,5/, N/sub 4,5/, and O/sub 4,5/, thresholds. At L/sub 3/ and M/sub 3/, similar spectra with analogous information are observed. While in the metallic U systems, the white lines at L/sub 3/ and M/sub 3/ show only minor variations in position and relative peak height, a shift of approx. =4 eV is observed between UCl/sub 3/ and UF/sub 4/, representing mainly the difference in Coulomb interaction between a 2p/sub 3/2/ core hole and the 5f configurations. The spectra at the M/sub 4,5/ and N/sub 4,5/ thresholds are dominated by intense absorption peaks due to 3d-5f and 4d-5f transitions probing directly the unoccupied 5f states. No multiplet structure due to 3d-5f or 4d-5f exchange interaction is resolved, but the linewidths of the M/sub 4,5/ peaks in the metallic U systems are found to decrease by approx. =20% with increasing U-U distance, reflecting a narrowing of the unoccupied 5f bands. The spectra at the O/sub 4,5/ thresholds, on the other hand, show well-resolved structures, which are atomiclike for ThF/sub 4/ and UF/sub 4/ and may be described by spin-orbit and exchange splitting of the 5d/sup 9/5f/sup 1/ and 5d/sup 9/5f/sup 3/ final states, respectively. In metallic U systems, the O/sub 4,5/ structures are broadened and partly lost, presumably due to the more itinerant nature of the 5f states.
- Research Organization:
- Institut fuer Atom- und Festkoerperphysik, Freie Universitat Berlin, Arnimallee 14, D-1000 Berlin 33, Germany
- OSTI ID:
- 6046805
- Journal Information:
- Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 35:6; ISSN PRBMD
- Country of Publication:
- United States
- Language:
- English
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360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ABSORPTION SPECTRA
ACTINIDE COMPOUNDS
CHLORIDES
CHLORINE COMPOUNDS
COULOMB FIELD
COUPLING
CRYSTALS
DEBYE-SCHERRER METHOD
DIFFRACTION METHODS
ELECTRIC FIELDS
ENERGY LEVELS
EXCHANGE INTERACTIONS
F STATES
FINE STRUCTURE
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
HOLES
INTERACTIONS
INTERMEDIATE COUPLING
L-S COUPLING
LINE NARROWING
MONOCRYSTALS
POLYCRYSTALS
SPECTRA
URANIUM COMPOUNDS
X-RAY SPECTRA