A Reassessment of 5f Occupation in Plutonium

TL;DR

This study re-evaluates the 5f electron occupation in plutonium using corrected spectroscopic measurements, finding lower values than previously reported, which impacts understanding of plutonium's electronic structure.

Contribution

The paper provides a revised assessment of 5f electron occupation in plutonium by correcting measurement flaws and performing detailed spectroscopic simulations.

Findings

Revised 5f occupation: alphaPu = 5.0 +/- 0.1, deltaPu = 4.9 +/- 0.2

Previous estimates of ~5.5 are significantly higher

Spectroscopic methods were refined for more accurate electronic structure analysis

Abstract

A detailed spectroscopic simulation of the original Pu N4,5 and O4,5 X-Ray Absorption Spectroscopy (XAS) has been performed. Additionally, a fundamental flaw in the Electron Energy Loss Spectroscopy (EELS) measurement has been corrected. Thus, the determination of the 5f occupation (n) in elemental Pu has been re-evaluated with the result that n = 5.0 +/- 0.1 for alphaPu and n = 4.9 +/- 0.2 for deltaPu. These values are significantly lower than the value of ~5.5 that was propagated earlier.