Theoretical and comparative investigations of Yb ion in MWO4 and M′MoO4 scheelites crystals (M=Sr, Pb, Ca, Ba) and (M′=Sr, Pb, Ca, Cd)

The crystal-field model is applied to a series of scheelites crystals (CaWO₄, SrWO₄, PbWO₄, BaWO₄, CdMoO₄, CaMoO₄, SrMoO₄ and PbMoO₄) doped with the Yb³⁺ ion. The calculated crystal-field parameters present a general trend of variation with M²⁺ ionic radius of the host cation. The maximum splitting ΔE of the ²F_7/2 manifold of the Yb³⁺ ion is then obtained as a function of N_V crystal-field strength parameters. The agreement between experimental results and theoretical predictions for all investigated systems is very satisfactory. The crystal-field effects are very important for the prediction of emission energies of the Yb³⁺ ion in different scheelites.