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Title: Effect of pressure on f-electron delocalization and oxidation in actinide dioxides

Using rstprinciplescalculations,wehaveinvestigatedf-electrondelocalizationandoxidationintheactinidedioxidesunderpressure.WhilstUO2isfoundonthevergeofaninsulatortometaltransitionattheequilibriumvolume,increasinglylargerpressuresarerequiredtodelocalizef-electronsinNpO2,PuO2,andAmO2,respectively49,112,and191GPa.Comparedtothisbroadrangeofpressures,theexper-imentallyobservedstructuraltransitions,inallfourdioxides,occurbetween30and40GPa,whichleadsustoconcludethattheassociatedvolumecollapseisnotduetof-electrondelocalization.Incontrast,oxi-dationofthedioxidesisfoundtobelinkedtothedegreeoff-electronlocalization,butitemergesthatfornaturallyoccurringpressures(<10GPa),higheroxidesonlyexistforUO2.
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [3]
  1. Daresbury Laboratory, UK
  2. ORNL
  3. University of Aarhus, Denmark
Publication Date:
OSTI Identifier:
1159501
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Nuclear Materials; Journal Volume: 451; Journal Issue: 1-3
Publisher:
Elsevier
Research Org:
Oak Ridge National Laboratory (ORNL)
Sponsoring Org:
SC USDOE - Office of Science (SC)
Country of Publication:
United States
Language:
English