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

Journal Article · Fri Aug 01 00:00:00 EDT 2014 · Journal of Nuclear Materials

DOI:https://doi.org/10.1016/j.jnucmat.2014.03.057· OSTI ID:1159501

Petit, Leon ^[1]; Szotek, Zdzislawa ^[1]; Temmerman, Walter M ^[1]; Stocks, George Malcolm ^[2]; Svane, Axel ^[3]

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1. Daresbury Laboratory, UK
2. ORNL
3. University of Aarhus, Denmark

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.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1159501
• Journal Information: Journal of Nuclear Materials, Vol. 451, Issue 1-3; ISSN 0022-3115
• Publisher: Elsevier
• Country of Publication: United States
• Language: English