High Pressure Study of Localized States Related to Lanthanide Ions in Solids

The latest results on high pressure investigations of luminescence related to Pr3+and Eu2+ in different lattices are presented in this contribution. In the latter case the influence of pressure on anomalous luminescence in BaxSr1-xF2 for x=0, 0.3 and 0.5 and 1, and the LiBaF3:Eu2+ system as a function of pressure are presented and discussed. A theoretical model describing an impurity trapped exciton as a system where the first carrier is localized at the impurity and the second one is captured by the Coulomb potential at Rydberg–like states is developed. The model is used to analyze the anomalous luminescence in Eu2+ doped fluorides and pressure quenching of Pr3+ luminescence in oxides. The model explains the differences in the formation of an impurity trapped exciton in dependence, if the first excited impurity state belongs to 4fn or 4fn-15d1 electronic configurations