X-ray excited Auger transitions of Pu compounds

Abstract

X-ray excited Pu core–valence–valence and core–core–valence Auger line-shapes were used in combination with the Pu 4f photoelectron peaks to characterize differences in the oxidation state and local electronic structure for Pu compounds. The evolution of the Pu 4f core-level chemical shift as a function of sputtering depth profiling and hydrogen exposure at ambient temperature was quantified. The combination of the core–valence–valence Auger peak energies with the associated chemical shift of the Pu 4f photoelectron line defines the Auger parameter and results in a reliable method for definitively determining oxidation states independent of binding energy calibration. Results show that PuO2, Pu2O3, PuH2.7, and Pu have definitive Auger line-shapes. These data were used to produce a chemical state (Wagner) plot for select plutonium oxides. This Wagner plot allowed us to distinguish between the trivalent hydride and the trivalent oxide, which cannot be differentiated by the Pu 4f binding energy alone.

Quantitative XPS of plutonium: Evaluation of the Pu4f peak shape, relative sensitivity factors and estimated detection limits

“…The other elements can be in the form of impurities either on the surface or dissolved in the bulk material or from the intended preparation of alloys and compounds. Examples of elements that afford Pu4f spin–orbit peaks with a similar binding energy position and line shape to the satellite feature are Pu–Am alloys, 34 Pu–U alloys, 35 PuFe 2 36 and a range of compounds with plutonium formally in the +3 oxidation state that consist of PuPd 3 , 37 PuSb, 38 PuC, 39 Pu 2 O 3 , 40 PuN, 41 PuH x ( x = 2–3) 42 . Some of these elements are impurities occurring either from the processing environment or the radioactive decay of plutonium as highlighted in the survey spectrum of the δ‐Pu(Ga) alloy shown in Figure 1.…”

“…Examples of elements that afford Pu4f spin-orbit peaks with a similar binding energy position and line shape to the satellite feature are Pu-Am alloys, 34 Pu-U alloys, 35 PuFe 2 36 and a range of compounds with plutonium formally in the +3 oxidation state that consist of PuPd 3 , 37 PuSb, 38 PuC, 39 Pu 2 O 3 , 40 PuN, 41 PuH x (x = 2-3). 42 Some of these elements are impurities occurring either from the processing environment or the radioactive decay of plutonium as highlighted in the survey spectrum of the δ-Pu(Ga) alloy shown in Figure 1. The localized or Pu 3+ Pu4f spectrum from Pu 2 O 3 acquired from the native oxide film on the α-Pu sample is included in Figure 2 for comparison.…”

Density-functional study of plutonium monoxide monohydride

“…The corrosion of plutonium have been attracting considerable interest in surface chemistry, corrosion chemistry and condensed matter physics [1][2][3][4][5][6][7][8][9]. In addition, it is also an important issue for handling and storage of this chemically active and radioactive material [4,10].…”