Simulation of 4f–5d transitions of Yb2+in potassium and sodium halides

The free ion energy level parameters of Yb 2+ are obtained by fitting the 4f 13 5d Yb 2+ free ion energy levels. A model is proposed for scaling these parameters so that they are appropriate for Yb 2+ in crystals. Treating the scaling factor, the barycenter energy E exc of the 4f 13 5d configuration, and the crystal-field splitting parameter B 4 (dd) as free parameters and adopting the 4f crystal-field parameters of the 4f 13 configuration Yb 3+ ion in other hosts with the same ligands, the absorption spectra of Yb 2+ in MX (M = K, Na; X = F, Cl, Br, I) hosts are well simulated. A model is proposed for taking the effect of charge compensation into account and this shows that the inclusion of charge compensation effects does not significantly alter the calculated electronic absorption spectra but may considerably change the dynamics of the system.