Band structure aspects of materials with localizing f-orbitals

In those materials where the f-states are hybridized, a band structure provides a reasonable description of the ground state. This is amply demonstrated by the successful determination of the Fermi surfaces of CeSn3, URh3, Ulr3, and UGe3. But when the f-states become more local, inadequacies of the functionals employed yield incomplete localization. Thus, to obtain a good description of the Fermi surface for high field ferromagnetic CeSb, the local character of the f-orbitals is artifically forced to produce the standard rare earth model. When dealing with excited states, the ground state band structure provides only part of the story. Even thermal excitations can provide significant departures from the ground state as evidenced by the large enhancements found for some materials. The series USi3, UGe3, and USn3 (together with CeSn3) demonstrate the effect very well. NpSn3 provides a useful counter example demonstrating that such enhancements need not be a universal property of localization