Simple way to test the validity of 2S+1LJ barycenters of rare earth ions (e.g. 4f2, 4f3 and 4f6 configurations)

The energy displacement of non-degenerated electronic L-2S+1(f) levels, (J=0 or 1/2), along the nephelauxetic scale of a rare earth ion can be easily connected with the evolution of the barycenter position of different 2S+1Lf levels of 4f(n) ground configurations. Linear slopes are obtained and presented for different crystal field (cf) levels for Nd3+, Pr3+ and Eu3+, corresponding to the 4f(2), 4f(3) and 4f(6) configurations, respectively. A L-25+1(f) level barycenter positioned out of slope suggests incorrect assignment of the level. Moreover, some missing Stark components of a given L-2S+1(f) level can be correctly extrapolated on the basis of the corresponding barycenter deduced from the slope. It is particularly evident in the case of low J values. The example of the P-2(3/2) level for Nd3+ doped Ca4GdO(BO3)(3) (GdCOB) crystal is given as an illustration. (C) 2000 Elsevier Science S.A. All rights reserved.