On the electronic configuration in Pu:: spectroscopy and theory

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 not equal 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.