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On the valence fluctuation in the early actinide metals

Journal Article · · Journal of Electron Spectroscopy and Related Phenomena
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  1. Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
  2. Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
  3. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
  4. SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
+ Show Author Affiliations
In this study, recent X-ray measurements suggest a degree of valence fluctuation in plutonium and uranium intermetallics. We are applying a novel scheme, in conjunction with density functional theory, to predict 5f configuration fractions of states with valence fluctuations for the early actinide metals. For this purpose we perform constrained integer f-occupation calculations for the α phases of uranium, neptunium, and plutonium metals. For plutonium we also investigate the δ phase. The model predicts uranium and neptunium to be dominated by the f3 and f4 configurations, respectively, with only minor contributions from other configurations. For plutonium (both α and δ phase) the scenario is dramatically different. Here, the calculations predict a relatively even distribution between three valence configurations. The δ phase has a greater configuration fraction of f6 compared to that of the α phase. The theory is consistent with the interpretations of modern X-ray experiments and we present resonant X-ray emission spectroscopy results for α-uranium.
Research Organization:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
Sponsoring Organization:
USDOE; USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division (MSE); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF)
Grant/Contract Number:
AC02-05CH11231; AC02-76SF00515; AC52-06NA25396; AC52-07NA27344
OSTI ID:
1248266
Alternate ID(s):
OSTI ID: 1409777
OSTI ID: 1436591
OSTI ID: 22565195
OSTI ID: 1252027
OSTI ID: 2530945
Report Number(s):
LA-UR--17-24461; LA-UR-17-24461; LLNL--JRNL-672996
Journal Information:
Journal of Electron Spectroscopy and Related Phenomena, Journal Name: Journal of Electron Spectroscopy and Related Phenomena Journal Issue: C Vol. 207; ISSN 0368-2048
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English

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Cited By (2)

Density-functional theory for plutonium journal January 2019
Probing 5 f -state configurations in URu 2 Si 2 with U L III -edge resonant x-ray emission spectroscopy journal July 2016

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75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
X-ray emission spectroscopy
actinides
density functional theory
valence fluctuations