On the VUV and UV 4f7(8S)5d > 4f8 interconfigurational transitions of Tb3+ ions in LiLuF4 single crystal hosts

The laser induced fluorescence spectrum of Tb3+ ions in LiLuF4 single crystals, pumped by a fluorine pulsed discharge molecular laser at 157.6 nm, was obtained in the vacuum ultraviolet (VUV) and ultraviolet (UV) regions of the spectrum. The 4f75d > 4f8 dipole allowed transitions originate from the Stark components and the edge of the levels of the 4f7(8S)5d electronic configuration. The LIF spectra were interpreted on the basis of phonon trapping and phonon reabsorption within the levels of the 4f75d electronic configuration. The absorption spectrum of the crystal samples in the VUV was obtained as well. We observed eight transitions between the ground level 4f8(7F6) and the Stark components of the levels of the 4f7(8S)5d electronic configuration and five transitions between the ground level 4f8(7F6) and the Stark components of the levels of the 4f7(6P)5d electronic configuration. The edge of the levels of the 4f75d electronic configuration was found to be at 45.2 × 103 ± 0.2 × 103 cm-1 and the band gap of the crystal host was 77.6 × 103 ± 0.3 × 103 cm-1 wide. © 1998 Elsevier Science B.V. All rights reserved