The role of f electrons in rare-earth and uranium intermetallics

Electronic structures of Nd³⁺ and U³⁺ ions in NdNi₅ and UPd₂Al₃ intermetallic compounds have been discussed. The strong correlation between the charge distribution at the vicinity of the f-shell electrons and the magnetic state of the f electron subsystem of these Kramers ions has been underlined. The formation of the local magnetic moment, of the ordered magnetic state, of the singlet ground state and of the energy gap in the ordered state is evaluated in conjugation with the temperature dependence of the energy level scheme. It is argued that as a function of the charge distribution and the spin-dependent interactions many exotic properties are expected resembling those found in heavy-fermion compounds