A diagonalization (of the energy matrix for which the Hamiltonian contains the free ion, crystal-field interaction and Zeeman interaction terms) method was applied to calculate the spin-Hamiltonian parameters (g factors, g|| and g﬩ and five zero-field splittings) for the tetragonal Gd3+ center in cubic c-RbZnF3 perovskite. The calculated results were in reasonable agreement with experimental values. From the calculation, the defect model that the tetragonal Gd3+ center was attributed to Gd3+ occupying the 12-fold coordinated Rb+ site associated with a nearest Rb+ vacancy, VRb, along C4 axis owing to charge compensation was confirmed and the defect structural data of this Gd3+ impurity center in c-RbZnF3 were acquired.

Theoretical Studies of the Spin-Hamiltonian Parameters and Defect Structure for the Tetragonal Gd3+ Center in Cubic c-RbZnF3 Crystal. W.C.Zheng, W.Q.Yang, H.G.Liu: Philosophical Magazine, 2011, 91[31], 4045-52