A set of empirical calculations for the 'strong' crystal field have been performed, and values of the relevant parameters for the U4+ ion in UO2 crystals are reported. The 9-fold degeneracy of the free-ion ground state 3H4 of an uranium ion is partially lifted, and is split into a four-level system of a singlet A1, a doublet E, and two triplets T1 and T2 levels. The experimental data on the neutron spectroscopy can be fitted to theory by choosing values of the parameters as B40 = 893.3 meV, B60 = 387.7 meV. The low value of B40 thus obtained suggests that the system can adequately be treated with the 'weak' Crystal Field approach, and ground state wavefunction 3H4 can be almost entirely expressed within a single J = 4 manifold, as is the case for lanthanide systems. The calculated Landé g value of the ground state T2 is 0.8232, and those of the first three excited levels E, T1, A1 are 0.8286, 0.8389, 0.8083 respectively.
|Number of pages||4|
|Publication status||Published - Jul 1998|