Vacuum ultraviolet photoluminescence of NaMgF:Sm and NaMgF:Sm,Ce: energy levels of the lanthanides in NaMgF:Ln compounds.

The luminescence properties of NaMgF:Sm and NaMgF:Ce,Sm were studied in the vacuum ultraviolet spectral region. Excitation bands corresponding to the charge transfer processes F → Sm, O → Sm, and O → Ce, and the energy transfer processes Ce → Smand O → Sm, were observed. The energies of the Smcharge transfer transitions and the crystal field split Ce45transitions were used to construct a complete host referred binding energy diagram for the series of lanthanide-doped NaMgF:Ln compounds. We demonstrate that the optical and luminescence properties predicted by the binding energy diagram are in good agreement with those predicted by the binding energy diagram constructed via the alternative impurity-informed method, and all available experimental data regarding the NaMgF:Ln compounds. We demonstrate that NaMgF:Ln compounds are model systems for the study of charge trapping phenomena and divalent lanthanide luminescence. Ultimately, we validate that the impurity-informed method can be used to establish the energy levels of lanthanides in fluoride systems.