Studies of the Spin Hamiitonian Parameters for NiX2 and CctX2:Ni2+ (X = Ci, Br)

摘要

The spin Hamiitonian parameters (zero-field splitting D and the g factors) for N1X2 and CdX2:Ni2+ (X=C1, Br) are quantitatively investigated from the perturbation formulas of these parameters for a 3d8 ion in trigonally distorted octahedra based on the cluster approach. In the calculations, the trigonal field parameters v and v' are determined from the superposition model and the local structures of Ni2+ in the halides, The theoretical g factors show reasonable agreement with the observed values, and the experimental D for CdX2:Ni + are also interpreted by considering suitable lattice distortions (angular decreases) in the impurity-ligand bond angles related to the C3 axis due to the size mismatching substitution, The contributions from the ligand orbital and spin-orbit coupling interactions are important and should be taken into account.