Theoretical Studies of Electron Paramagnetic Resonance Parameters for Cr~(4+) Ions in Ca_2GeO_4 Crystals

摘要

The electron paramagnetic resonance (EPR) parameters (zero-Geld splitting D and g factors g_‖, g_⊥) of Cr~(4+) ions in Ca_2 GeO_4 crystals have been calculated from the complete high-order perturbation formulas of EPR parameters for a 3d~2 ion in trigonal MX_4 clusters. In these formulas, in addition to the contributions to EPR parameters from the widely used crystal-field (CF) mechanism, the contributions from the charge-transfer (CT) mechanism (which are often neglected) are included. From the calculations, it is found that for the high valence state 3d~n ions in crystals, the reasonable explanation of EPR parameters (in particular, the g factors) should take both the CF and CT mechanisms into account.