Local structures of rare-earth ions in glasses: the ‘crystal-chemistry’ approach

Abstract

A ‘crystal-chemistry’ model is proposed to evaluate the rare-earth local structure in glass based on the modified-random-network (MRN) model in glass structure. Three influential factors are summarized, concerning the coordination number, the regularity of the site around the ion, and the spacing between ions. The spectral properties of rare-earth ions in glasses is well described and predicted by the proposed ‘crystal-chemistry’ model. The concentration-quenching effect of rare-earth ions in glasses in terms of ion-ion separation is analyzed by this model in relation to the role as glass-modifier or glass-intermediate of the rare-earth ion in the glass. The model suggests that glasses in which the rare-earth ions act as intermediates are likely to show less concentration-quenching effect.