Optical absorption and laser excited fluorescence spectra of LaF₃:Eu³⁺

Abstract

The optical absorption spectrum of LaF₃:Eu³⁺ single crystal at liquid nitrogen temperature (LNT) showed two groups of lines around 5240 and 4640 Å which are attributed to the Stark levels associated with the ⁵D₁ and ⁵D₂ of Eu³⁺. The fluorescence spectrum of this system at LNT excited with the 4580 and 5145 Å lines of the Ar⁺ laser revealed 12 groups of lines originating in the Stark components of ⁵D_0,1,2 and terminating in those of the ⁷F_0,1,2,3,4,5 levels. Most of the Stark components of the energy levels of the LaF₃:Eu³⁺ system lying below 20000 cm⁻¹ could be determined from these spectra. The polarizations of the lines indicate a C_2v site symmetry, and all the observed Stark components are categorized under the symmetry species of this group.