Optical Absorption and Fluorescence Spectra of EuF3

The absorption spectrum of EuF3 powder has been obtained in the region from 1.8–10μm. By means of a diffuse reflection technique, the crystal sublevels of the 5D0,1,2 states were obtained at liquid-nitrogen temperature. Fluorescence from the 5D0 state and from some of the crystal sublevels of the 5D1,2 states to the 7FJ(J = 0, 1, 2, 3, 4, 5, 6) states has been observed. From an analysis of the observed transitions, it was possible to assign 2J+1 Stark components to the observed states, in agreement with the Cs site symmetry for Eu3+ in EuF3. The intermediate coupling free-ion energy levels for Eu3+ have been calculated, including the interactions of all the multiplets of the f6 configuration. Values of F2=351.5 cm−1, F4=57.64 cm−1, F6=5.625 cm−1, and ζ=1328 cm−1 are found to give the best over-all agreement between the observed and calculated energy levels.