On the electronic configuration in Pu: spectroscopy and theory

Abstract

Photoelectron spectroscopy, synchrotron-radiation-based x-ray absorption, electron energy loss spectroscopy, and density-functional calculations within the mixed-level and magnetic models, together with canonical band theory, have been used to study the electron configuration in Pu. These methods suggest a 5f n occupation for Pu of 5 n < 6, with n = 6, contrary to what has recently been suggested in several publications. We show that the n = 6 picture is inconsistent with the usual interpretation of photoemission, x-ray absorption, and electron energy loss spectra. Instead, these spectra support the traditional conjecture of a 5f 5 occupation in Pu as is obtained by density-functional theory. We further argue, based on 5f-band filling, that an n = 6 hypothesis is incompatible with the position of Pu in the actinide series and its monoclinic ground-state phase.

The influence of defects on magnetic properties of fcc-Pu

“…The later has the largest occupation number in all considered structures (see the tables below). The large number of f electrons (close to 6) obtained in the present calculation disagrees with previous experimental and theoretical estimations that give 5.1-5.2 electrons [26]. Such a difference between theoretical results originates from dissimiliar band structure calculation methods.…”

Multiconfigurational nature of 5f orbitals in uranium and plutonium intermetallics

“…For example, elemental Pu is thought to have an f-orbital occupancy near 5, close to that expected for a 5f 5 ground-state configuration (Pu 3þ ) based on photoemission, N 4;5 -edge X-ray absorption, and electron-energy loss spectroscopy (4,5). In addition to these examples, several researchers have shown that so-called "two-fluid" or "dual nature" models of the 5f orbitals, whereby some fraction of the f-electrons contribute to delocalized behavior and the rest contribute to the more localized local moment behavior, can successfully describe some properties (6) such as coexistent antiferromagnetism and superconductivity in CeRhIn 5 (7), the inelastic neutron scattering of UPd 2 Al 3 (8), de Haas-van Alphen frequencies of UPt 3 (9), and the photoemission spectra of PuCoGa 5 and PuIn 3 (10).…”

Pressure-induced changes in the electronic structure of americium metal

“…Further affirmation is given by a canonical band model with itinerant f electrons, which shows that precisely AmIV is favored over other plausible phases for f occupations corresponding to Am. 32 Another hint that full delocalization has occurred for AmIV is the fact that the magnetic moments are all suppressed at this pressure in the calculations. Any remaining 5f -localization in Am would have manifested itself through spin polarization in the DFT treatment as a necessary but not sufficient condition.…”