Fluorescence spectrum, energy level scheme and crystal field analysis of europium(+III) doped lanthanum magnesium borate LaMgB₅O₁₀:Eu³⁺

Abstract

The fluoresence spectrum of europium(+III) doped LaMgB₅O₁₀ was studied at 77 and 300K under U.V. and visible dye laser excitation. A phenomenological crystal field analysis was conducted on the basis of the observed 34 ⁷ F _0-5 level energies. A descending symmetry method from D _2d to C _2v and C ₂ symmetries was used in the simulation. D _2d simulation was found to be inadequate to describe the experimental energy level scheme whereas for C _2v symmetry a satisfactory r.m.s. deviation of 7·1 cm^-1 was obtained. The decrease in symmetry to C ₂ did not improve the simulation. The weak ⁵ D ₀ → ⁷ F ₀ transition intensity was found to correlate with the mixing of the ⁷ F _2,4 wave functions with the ⁷ F ₀₀ one.