LUMINESCENCE OF THE EUROPIUM(III) DOPED HIGH-TEMPERATURE AND PRESSURE MODIFICATION OF RARE-EARTH DISILICATES

The UV and dye laser excited optical luminescence spectra at 77 and 300 are reported for the D-Y2Si2O7:Eu3+ and D-Lu2Si2O7:Eu3+ systems obtained at high temperature and pressure. The 7F0-5 energy level schemes derived from this study are analyzed in terms of a 14 parameter crystal field (cf.) Hamiltonian in a c.f. of C2 symmetry. The parameter sets are used to simulate the experimental energy level schemes. The best fit sets of the cf. parameters yield excellent simulation of the experimental c.f. splittings of the 7F0-5 - energy levels with r.m.s. deviations between 5 and 6 cm-1. The strength of the c.f. effect decreases slightly with increasing ionic radius of the RE host. The experimental parameter sets are rather similar to those obtained for the low pressure form of RE disilicates, C-RE2Si2O7.:Eu3+, but differ from those of the RE oxysalts (oxyhalides, oxysulfates and oxymolybdates/oxytungstates). © by R. Oldenbourg Verlag