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Title: Probing the population of the spin-orbit split levels in the actinide 5f states

Abstract

Spin-orbit interaction in the 5f states is believed to strongly influence exotic behaviors observed in actinides metals and compounds. Understanding these interactions and how they relate to the actinide series is of considerable importance. To address this issue, the branching ratio of the white-line peaks of the N4,5 edges for the light actinide metals, {alpha}-Th, {alpha}-U, and {alpha}-Pu were recorded using electron energy-loss spectroscopy (EELS) in a transmission electron microscope (TEM) and synchrotron-radiation-based x-ray absorption spectroscopy (XAS). Using the spin-orbit sum rule and the branching ratios from both experimental spectra and many-electron atomic spectral calculations, accurate values of the spin-orbit interaction, and thus the relative occupation of the j = 5/2 and 7/2 levels, are determined for the actinide 5f states. Results show that the spin-orbit sum rule works very well with both EELS and XAS spectra, needing little or no correction. This is important, since the high spatial resolution of a TEM can be used to overcome the problems of single crystal growth often encountered with actinide metals, allowing acquisition of EELS spectra, and subsequent spin-orbit analysis, from nm-sized regions. The relative occupation numbers obtained by our method have been compared with recent theoretical results and show a goodmore » agreement in their trend.« less

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
881891
Report Number(s):
UCRL-JRNL-206133
Journal ID: ISSN 0304-3991; ULTRD6; TRN: US0603032
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Journal Article
Journal Name:
Ultramicroscopy
Additional Journal Information:
Journal Volume: 106; Journal Issue: 4-5; Journal ID: ISSN 0304-3991
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABSORPTION SPECTROSCOPY; ACTINIDES; BRANCHING RATIO; ELECTRON MICROSCOPES; ELECTRONS; ENERGY-LOSS SPECTROSCOPY; L-S COUPLING; MONOCRYSTALS; OCCUPATION NUMBER; OCCUPATIONS; SPATIAL RESOLUTION; SPECTRA; SUM RULES

Citation Formats

Moore, K, der Laan, G v, Tobin, J, Chung, B, Wall, M, and Schwartz, A. Probing the population of the spin-orbit split levels in the actinide 5f states. United States: N. p., 2004. Web.
Moore, K, der Laan, G v, Tobin, J, Chung, B, Wall, M, & Schwartz, A. Probing the population of the spin-orbit split levels in the actinide 5f states. United States.
Moore, K, der Laan, G v, Tobin, J, Chung, B, Wall, M, and Schwartz, A. Wed . "Probing the population of the spin-orbit split levels in the actinide 5f states". United States. https://www.osti.gov/servlets/purl/881891.
@article{osti_881891,
title = {Probing the population of the spin-orbit split levels in the actinide 5f states},
author = {Moore, K and der Laan, G v and Tobin, J and Chung, B and Wall, M and Schwartz, A},
abstractNote = {Spin-orbit interaction in the 5f states is believed to strongly influence exotic behaviors observed in actinides metals and compounds. Understanding these interactions and how they relate to the actinide series is of considerable importance. To address this issue, the branching ratio of the white-line peaks of the N4,5 edges for the light actinide metals, {alpha}-Th, {alpha}-U, and {alpha}-Pu were recorded using electron energy-loss spectroscopy (EELS) in a transmission electron microscope (TEM) and synchrotron-radiation-based x-ray absorption spectroscopy (XAS). Using the spin-orbit sum rule and the branching ratios from both experimental spectra and many-electron atomic spectral calculations, accurate values of the spin-orbit interaction, and thus the relative occupation of the j = 5/2 and 7/2 levels, are determined for the actinide 5f states. Results show that the spin-orbit sum rule works very well with both EELS and XAS spectra, needing little or no correction. This is important, since the high spatial resolution of a TEM can be used to overcome the problems of single crystal growth often encountered with actinide metals, allowing acquisition of EELS spectra, and subsequent spin-orbit analysis, from nm-sized regions. The relative occupation numbers obtained by our method have been compared with recent theoretical results and show a good agreement in their trend.},
doi = {},
url = {https://www.osti.gov/biblio/881891}, journal = {Ultramicroscopy},
issn = {0304-3991},
number = 4-5,
volume = 106,
place = {United States},
year = {2004},
month = {7}
}