The J-mixing effect in Ln3+ ions crystal field levels

The J-mixing effect in the 2S+1LJ level barycentre energy and splitting of trivalent lanthanide ions is analysed. The main predictions are that the maximum 2S+1LJ level splitting (ΔE) is reduced and the barycentre energy can become lower with increasing ΔE. This effect is particularly important in low symmetries. Satisfactory agreement between the predictions and experimental data was obtained to all analysed systems, namely, the maximum 7F1 level splitting of the Eu3+ ion and its barycentre energy in crystals and glasses.