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 4fd, 6s transitions 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 5p5d 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. © 1978 The American Physical Society.
Optical properties of single crystals of some rare-earth trifluorides, 5-34 eV / C. G., Olson; Piacentini, Mario; D. W., Lynch. - In: PHYSICAL REVIEW. B, CONDENSED MATTER. - ISSN 0163-1829. - STAMPA. - 18:10(1978), pp. 5740-5749. [10.1103/physrevb.18.5740]
Optical properties of single crystals of some rare-earth trifluorides, 5-34 eV
PIACENTINI, Mario;
1978
Abstract
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 4fd, 6s transitions 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 5p5d 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. © 1978 The American Physical Society.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.