Quenching Interactions between Rare-Earth Ions

Abstract

Interactions between identical or nonidentical rare‐earth ions that result in the quenching of fluorescence of Eu³⁺ or Tb³⁺ have been studied. Comparison of the intensities of emission of Eu³⁺ as a function of its concentration in various oxides indicates that interactions that result in the quenching of emission from the ⁵D₀ levels of the Eu³⁺ ions are associated with pairing through intervening oxygen ions. Higher‐lying levels appear to be quenched by interactions through anionic groups (e.g., WO₄^2—). The quenching effects that a dissimilar rare‐earth ion M has on the emission of Eu³⁺ or Tb³⁺ in the sodium rare‐earth tungstates correlate with (1) the energy gap between the fluorescing level of the latter and the closest lower‐lying level of M, and (2) the total orbital angular momentum of the ground state of M.