Magnetism and fine electronic structure of UPd2Al3 and NpPd2Al3

We claim the existence of the f(3) (U3+) configuration in UPd2Al3. It is in agreement with inelastic-neutron-scattering (INS) excitations and is consistent with the trivalent neptunium configuration in NpPd2Al3. We have derived a set of CEF parameters for the U3+ state that better reproduces the INS excitations and temperature dependence of the heat capacity. On the basis of the crystal-field theory, extended to the Quantum Atomistic Solid State Theory (QUASST) we argue that the uranium magnetic moment amounts to 1.7-1.8 mu(B) at 0 K and the Np moment in NpPd2Al3 points along the hexagonal c axis.