EPR parameters and optical spectrum of α-Al2O3:Ti3+ with dynamic Jahn-Teller effect

The quenching phenomenon of trigonal crystal field (CF), spin–orbit (SO) coupling operators, and orbital operators reflected in electron paramagnetic resonance (EPR) parameters and energy splitting intervals observed in experiments of α -Al ₂O ₃:Ti ³⁺ is theoretically investigated by the calculation of EPR g factors and the energy differences of the lowest three levers E _3/2, ¹ E _1/2 and ² E _1/2 with the formulas derived with high-order perturbation method. In the calculation, the coupling of ² T _2g and ² E _g with e vibrational model of dynamic Jahn-Teller effect are considered. The calculated results are in agreement with the experimental values. The local defect structure around Ti ³⁺ ions (bond lengths and angles of [TiO ₆] ^9-) and trigonal CF parameters ν and v ′ are determinedand the covalence effects on SO coupling parameters ζ, ζ ^’ and orbital reduction parameters k、 k ^’ are determined also.