Studies of electron paramagnetic resonance parameters and structure of Ni2+-vacancy center for rhombic LiCl:Ni2+ crystal

Abstract High-order perturbation formulae for the electron-paramagnetic-resonance (EPR) parameters g -factors ( g x , g y and g z ), and zero-field splitting (ZFS) parameters D and E of the ground state 3 A 2g of 3d 8 ions in the crystal field (CF) with rhombic symmetry ( C 2v ) have been derived in the strong field scheme, using the molecular orbital (MO) scheme for the first time, and applied to the investigation of Ni 2+ (3 d 8 ) ions doped in LiCl crystal. In the derivation, both the contributions from all the crystal field excited states and the most important charge-transfer (CT) excited states to the EPR parameters are taken into account. The relations between the EPR parameters and the local structure parameters are established, and the defect of Ni 2+ -V c center are determined quantitatively. In addition, the Clebsch-Gordan (C-G) coefficients used to construct wavefunctions in the second-kind coordinate system are calculated and given.