Journal or Book Title
Physical Review B
The reflectances of single crystals of the trifluorides of La, Ce, Pr, Nd, Dy, and of polycrystalline GdF3 were measured in the 10-34-eV region, along with 5-9-eV transmission measurements on films of these materials. Localized 4f→5d, 6stransitions on the rare-earth ions give rise to the absorption below 10 or 11 eV. Strong interband absorption gives anisotropic reflectance peaks in the 10-15-eV region, presumably from F− 2p valence bands to lanthanide 5d, 6s (and other states) conduction bands, accounting for about one-third of the expected F− 2p osillator strength. Transitions from lanthanide 5p levels cause two types of spectra beginning around 20 eV: transitions of the 5p→5d type, apparently localized on lanthanide ions, but with some an isotropy; and transitions of 5p electrons to the conduction band, giving a peak of very high reflectance at energies above 27 eV.
The American Physical Society
Olson, C. G.; Piacentini, M.; and Lynch, David W., "Optical properties of single crystals of some rare-earth trifluorides, 5-34 eV" (1978). Physics and Astronomy Publications. 55.