Sonoluminescence of chelated terbium(III) in aqueous solution

Abstract

Tb^III chelates containing aromatic moieties show sonoluminescence in aqueous solutions during the sonolysis of water. The observed ⁵D₄→⁷F_J transitions of Tb^III are due to the excitation of ligand, followed by an intramolecular energy transfer from the ligand to the central ion, which finally emits. No sonoluminescence of hydrated or EDTA-chelated Tb^III ion could be observed. Ligand excitation can be based either on an energy transfer from the intrinsic emission centres of the sonolysis of water to the aromatic ligand, or on redox reactions between the ligand and hydroxyl radicals and hydrogen atoms produced by the sonolysis of water. Experimental results give greater support to the latter, chemiluminescent, excitation pathway.