Simulation of crystal field effect in monoclinic rare earth oxyhydroxides doped with trivalent europium

Abstract

The visible luminescence spectra of the monoclinic form of the Eu{sup 3+}-doped rare earth oxyhydroxides, REOOH:Eu{sup 3+} (RE = La, Gd, Y, and Lu), recorded at 77 K are reported and analyzed. The {sup 7}F{sub 0-4} experimental energy level schemes were simulated with the aid of the phenomenological crystal field (cf) theory. The sets of the nine nonzero cf parameters for the C{sub 2v} symmetry reproduce the experimental energy level schemes in a satisfactory manner (with rms deviations between 5.7 and 11.5 cm{sup {minus}1}) in spite of the real symmetry of the RE site being lower, C{sub s}. The parameter values as well as the strength of the cf effect vary only slightly within the structurally isomorphic REOOH series. The cf effect is weak when compared to that in rare earth oxyhalides, oxysulfates, and oxymolybdates/oxytungstates studied previously.