Multibubble sonoluminescence of europium(III) chloride in heavy water

A weak glow in the region of the Eu³⁺ photoluminescence spectrum was detected against the background of the continuum of the solvent emission during multibubble sonolysis of air- or argon-saturated EuCl₃ solutions (0.1 mol L⁻¹) in heavy water. No characteristic sonoluminescence of the europium ion in aqueous solutions was observed earlier. Possible reasons for the low yield of Eu³⁺ sonoluminescence compared with other lanthanide ions (Ln³⁺) are discussed and the influence of europium on the spectrum of the solvent continuum related, in particular, to quenching of the electron-excited sonolysis products H₂O* (D₂O*) and Eu³⁺* in electron transfer reactions. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1793–1796, September, 2008.