title: The behavior of f-levels in hcp and bcc rare-earth elements in the ground state and XPS and BIS spectroscopy from density-functional theory.
abstract: The electronic structures of rare-earth elements in the hexagonal close-packed structure and Europium in the body-centered cubic structure are calculated using density-functional theory (DFT). X-ray photoemission spectroscopy (XPS) and bremsstrahlung isochromatic spectroscopy (BIS) simulations are made within DFT by implying that the f-electrons are excited by a large photon energy, either by removal from the occupied states in XPS or by addition to the unoccupied f-states in BIS. The results show sizable differences in the apparent position of the f-states compared to the f-band energy of the ground states. This result is fundamentally different from calculations assuming strong on-site correlation, since all the calculations are based on DFT. The spin-orbit coupling and multiplet splittings are not included, and the present simulation accounts for almost half of the difference between the f-level positions in the DFT ground states and the observed f-level positions. The electronic specific-heat at low T is compatible with the DFT ground state, where f-electrons often reside at the Fermi level.
authors.affiliation: DPMC, University of Geneva, 24 Quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland.
authors.forename: T
authors.initials: T
authors.lastname: Jarlborg
mesh_terms: D003198:Computer Simulation; D018360:Crystallography, X-Ray; D004583:Electrons; D005063:Europium / Q000737:chemistry*; D008674:Metals, Rare Earth / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D056951:Photoelectron Spectroscopy; D011789:Quantum Theory; D013113:Spin Labels
chemical_list: D008674:Metals, Rare Earth; D013113:Spin Labels; D005063:Europium