Spin-Hamiltonian parameters and defect structure for the rhombic Dy3+ center in AgCl crystal

Based on the defect model that the rhombic Dy(3+) center in AgCl crystal is formed by substitutional Dy3+ ion associated with two nearest Ag+ vacancies (VAg) along the <110> and <110> axes owing to charge compensation, the spin-Hamiltonian parameters (g factors gi and hyperfine structure constants 161Ai and 163Ai, where i=x, y, z) of this rhombic Dy3+ center are calculated from a diagonalization (of energy matrix) method. In the method, the Zeeman (or magnetic) and hyperfine interaction terms are attached to the classical Hamiltonian used in the calculation of crystal-field energy levels and a 66×66 energy matrix concerning this Hamiltonian is constructed by taking all the ground-term multiplets 6HJ (J=15/2, 13/2, 11/2, 9/2, 7/2, 5/2) into account. The calculated results (g factors gi and average |A(161Dy3+)| and |A(163Dy3+)|) are in reasonable agreement with the experimental values. From the calculations, the above defect model of rhombic Dy3+ center is confirmed, the defect structure of this Dy3+ center (characterized by the displacement of Cl- ligand caused by VAg) is obtained and the components of hyperfine structure constants Ai(161Dy3+) and Ai(163Dy3+) are predicted. The results are discussed.