Parametrization of Crystal Field Splittings of the 7 F 7 Levels

The luminescence spectra of europium (3 + ) doped rare earth oxyhydroxides, REOOH :Eu 3 + (RE = Y and Lu), were studied and analyzed at 77 and 300 K under UV and dye laser excitation. The observed 7 F 0 _ 4 level schemes were simulated with the aid of the phenomenological crystal field theory. The descending symmetry method from C2 v to Cs symmetry was used in the simulation. Good results were obtained with C s symmetry simulation which yielded r.m.s. deviations of 6 and 7 c m 1 between the calculated and experimental 7 F 0 _ 4 level schemes for Y O O H : E u 3 + and LUOOH :EU 3 + , respectively. The C 2 v simulation was found inadequate to describe the experimental energy level schemes. The even rank crystal field parameters vary only slightly as a function of the host. Comparison with the corresponding values obtained for the monoclinic form of the Eu 3 + doped RE oxyhydroxides reveals significant differences.