Abstract：The optical spectra, the zero-field splitting parameter D and the g-factor of transition-metal ions in crystal are related to the crystal structure. A method，which can be used to calculate accurately the optical spectra, the zero-field splitting parameter D and the g-factor, was founded by using the parametriｚation d orbital for Ni2+, the energy matrix elements of strong-field coupling scheme for d2(d8) electron configuration in trigonal crystal field and by adopting the method of complete diagonalization. In the calculation, all spin singlet states and spin triplet states have been considered, and then the result is exact. The present theory shows that g∥>g⊥, D<0 or g∥<g⊥, and D>0 are due to the different distortion of ligands along C3 axis. The electron paramagnetic resonance spectrum in Ni2+:RbMgF3 with C3v and D3d symmetry was calculated by using the theory. The relationship between the EPR spectrum in Ni2+:RbMgF3 and the crystal structure were investigated. The agreement of the theory with the experiment shows that the present theory is reasonable.
Key words：Trigonal crystal field;d2(d8) electron configuration;Electron paramagnetic resonance
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