Publication Type
Journal
Journal Name
Journal of Nuclear Materials
Publication Date
Page Numbers
313 to 319
Volume
451
Issue
1-3
Abstract
Usingfirstprinciplescalculations,wehaveinvestigatedf-electrondelocalizationandoxidationintheactinidedioxidesunderpressure.WhilstUO2isfoundonthevergeofaninsulatortometaltransitionattheequilibriumvolume,increasinglylargerpressuresarerequiredtodelocalizef-electronsinNpO2,PuO2,andAmO2,respectively49,112,and191GPa.Comparedtothisbroadrangeofpressures,theexper-imentallyobservedstructuraltransitions,inallfourdioxides,occurbetween30and40GPa,whichleadsustoconcludethattheassociatedvolumecollapseisnotduetof-electrondelocalization.Incontrast,oxi-dationofthedioxidesisfoundtobelinkedtothedegreeoff-electronlocalization,butitemergesthatfornaturallyoccurringpressures(<10GPa),higheroxidesonlyexistforUO2.
