Ab-initio determination of the localized/delocalized f-manifold in UPd₂Al₃

The electronic structure of UPd_2Al_3 is described using the self-interaction corrected local-spin-density approximation to density functional theory. The groundstate is found to be characterized by the coexistence of localized (f^2) and delocalized U f electrons, in agreement with experimental evidence. We observe significant difference in electronic structure between UPd_2Al_3 and the previously studied UPt_3 compound. Even though a trend towards localization exists in UPt_3, the total energies and the density of states at the Fermi level favor a groundstate with localized f^1, rather than f^2 U ions.