Narrow Results

The spin Hamiltonian parameters, g factors g_‖ and g_⊥, for Nd³⁺ in ThGeO₄ are theoretically investigated from the perturbation formulas of the g factors for a 4f³ ion in tetragonal symmetry. In these formulas, the contributions to the g factors from the second-order perturbation terms and the admixture of various states are taken into account. It is found that the calculated g factors of this work are smaller than the experimental results, but close to those in the previous theoretical studies by Gutowska et al. Moreover, the calculated hyperfine structure constants A_‖ and A_⊥ as well as the energies of the ⁴I_9/2 Stark levels in this work are also consistent with those in the previous investigations. The discrepancy between theoretical and experimental g factors is discussed.