The 4f n↔4f n−15d transitions of the trivalent lanthanides in halogenides and chalcogenides

Information from the literature on the energy difference between the 4f n ground-state multiplet and the low lying 4f n−15d excited states of Ce3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, Tb3+, Dy3+, Er3+, Tm3+ and Yb3+ doped in about 60 different inorganic compounds has been gathered and studied. It will be demonstrated that once the energy of the first spin allowed 4f n→4f n−15d transition in any of the above-mentioned lanthanides in a specific compound is known, the corresponding transition energy of all other lanthanides if doped in that same compound can be predicted with an accuracy of typically ±600 cm−1. New estimates will be given for the energy of the first spin-allowed and some of the spin-forbidden fd transitions of all the free (gaseous) triply ionized lanthanides.