Effect of modifier ions on the covalency of Nd 3+ ions in cadmium borate glasses

Abstract

An investigation of the optical absorption spectra of 1 mol% Nd 3+ ions in cadmium borate glass and effect of network modifiers, alkali ions, Li, Na and K is presented. Special emphasis is laid on the position, intensity parameters, Ω λ,λ =2,4,6, of the 4I 9/2 → 4F 7/2, 4S 3/2, and hypersensitive 4I 9/2 → 4G 5/2 transitions. The effect of covalency of the rare earth ion sites on the transition probabilities was estimated from the variation of the profiles of the absorption spectra in terms of the nephelauxetic effect. The variation of intensity ratio and the Judd–Ofelt parameter, Ω 2 , with composition depended on the Nd–O covalency.