The Limitations of 5f Delocalization and Dispersion

Abstract

Delocalization in the 5f states of the actinides is an important phenomenon, but poorly quantified. Here, the fundamental limitations of 5f dispersion measurements using angle and momentum resolved variants of photoelectron spectroscopy will be discussed. A novel approach will be suggested, based on a theoretical projection, which should circumvent these limitations: M4,5 X-ray emission spectroscopy. This analysis will utilize the case study of U metal, which can be considered to be the paramount example of 5f dispersion.

Synchrotron Radiation Techniques and their Application to Actinide Materials

“…Although UO 3 was not specifically examined in the HERFD work of (Kvashnina et al, 2013), a number of such oxides were examined by x-ray core-hole photoemission, and there appears strong evidence that UO 3 consists of hexavalent U atoms (Ilton and Bagus, 2011). Work has also been reported on the branching ratios of UF 4 , UO 2 , and UCd 11 systems at the M 4,5 with a view to determining the occupied and unoccupied density of states (Tobin et al, 2019(Tobin et al, , 2021(Tobin et al, , 2015bYu et al, 2011).…”

Pu 5f Occupation in Plutonium Dioxide

“…Lower panel: plotted here are the experimental Wigner–Seitz radii, including the lanthanides, the actinides, and the 5d transition metal series. Taken from ref .…”