Quenching Interactions Involving the First Excited States of Gd, Yb, Er, Tm and Ho in Sodium Rare-Earth Tungstates

Abstract

Relative intensity of emission per ion and lifetime (τe) data have been obtained as a function of rare-earth (RE) ion concentration for the first excited states of Gd, Yb, Er, Tm, and Ho in Na0.5(Y, RE)0.5WO4 crystals. Excitation migration to quenching centers appears to be possible, even for rare-earth ions further apart than second-nearest (Y, RE) positions at room temperature but not at 4.2°K. A monopole–monopole-like interaction that enhances internal conversion and appears to be temperature independent is indicated also for the lower-lying first excited manifolds.