By using a defect model for the trigonal Dy3+-O2− center, electron paramagnetic resonance parameters (g factors, hyperfine structure constants) for this trigonal center were deduced from perturbation formulae. In the latter, the contributions to electron paramagnetic resonance parameters due to J-mixing among 6HJ (J = 15/2, 13/2 and 11/2) states were included. For the calculations, crystal field parameters were estimated from the superposition model. By using these calculations, the electron paramagnetic resonance g-factors (g||, g) could be reasonably explained and the superposition model intrinsic parameters, A2(F-) and A2(O2-) with R = 2.366Å, were obtained.

EPR Parameters and Superposition Model Analysis for Trigonal Dy3+–O2− Center in CaF2 Crystal. W.C.Zheng, H.N.Dong, S.Y.Wu, S.Tang: Physica B, 2004, 344[1-4], 103-7