P. Dorenbos, E. V. D. van Loef, A. P. Vink, E. van der Kolk, C. W. E. van Eijk, K. W. Krämer, H. U. Güdel, W. M. Higgins and K. S. Shah
Level location and spectroscopy of Ce³⁺, Pr³⁺, Er³⁺, and Eu²⁺ in LaBr₃
J. Lumin. 117, 147-155 (2006)                 

Abstract: The spectroscopic properties of LaBr₃ doped with Ce³⁺, Pr³⁺, Er³⁺, and Eu²⁺ under ultraviolet excitation are reported. LaBr₃ host excitation and emission, 4f–5d excitation and emission of Ce³⁺ and Eu²⁺, and charge transfer from the valence band to Pr³⁺ and Er³⁺ are observed. This experimental information is combined with an empirical model to estimate the position of the lowest 4f and lowest 5d state relative to the conduction band and valence band for each divalent lanthanide ion in LaBr₃. Existing literature data is used to determine the location of the lowest 4f and lowest 5d state for each trivalent lanthanide.