Abstract

The fluorescent properties of the trivalent rare earths were studied in the fluorite structure oxides, CeO₂ and ThO₂. In these compounds, the cations occupy sites of cubic symmetry, but the symmetry of the trivalent rare earth depends on the concentration and the manner of charge compensation. The emission spectra, fluorescent lifetimes, and excitation spectra were studied as functions of these variables. Multiple emission spectra of the trivalent ions were observed which varied with concentration and charge compensation. These changes were attributable to multiple sites for the rare earth under the various conditions. The multiple spectra could be well separated in the case of the ⁵D₀–⁷F₁ transition of Eu³⁺ in ThO₂ which shows at least three distinct spectra. A twofold enhancement of fluorescent lifetime was found to occur when the rare earth was placed in a predominantly cubic environment. The excitation spectra did not change detectably from those expected from known energy levels, but energy transfer was found to occur from the CeO₂ band edge (~38 000 cm⁻¹) to Eu³⁺, Sm³⁺, and Er³⁺.

© 1966 Optical Society of America

Energy Transfer between the Sm³⁺, Eu³⁺, Tb³⁺, and Dy³⁺ Ions in Sodium Rare-Earth Tungstates*

W. W. Holloway and M. Kestigian
J. Opt. Soc. Am. 56(9) 1171-1174 (1966)

Infrared Lattice Spectra of Cubic Rare Earth Oxides in the Region 700 to 50 cm⁻¹

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J. Opt. Soc. Am. 56(5) 636-638 (1966)

Phonon and Electronic Raman Spectra of Cubic Rare-Earth Oxides and Isomorphous Yttrium Oxide*

G. Schaack and J. A. Koningstein
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Ionization Energies of the Neutral Rare Earths

Joseph Reader and Jack Sugar
J. Opt. Soc. Am. 56(9) 1189-1194 (1966)

Optical Properties of Various Evaporated Rare Earth Oxides and Fluorides*

G. Hass, J. B. Ramsey, and R. Thun
J. Opt. Soc. Am. 49(2) 116-120 (1959)