Sonoluminescence of terbium chloride in an H2O-D2O mixture

The effect of solvent deuteration on the multibubble sonoluminescence (SL) of an aqueous solution of terbium chloride was studied. The dependence of the intensity of the characteristic SL of the Tb^III ion on the composition of an H₂O-D₂O mixture is similar to an analogous dependence of its photoluminescence (PL) but with a much smaller isotope effect. In pure D₂O, the SL intensity increases by 4 times only compared to the SL in water, while the PL intensity increases by 10 times. The mechanism of inner-bubble excitation of lanthanide ions is considered. According to this mechanism, an additional “heterogeneous” channel of quenching of excited Tb^III ions appears, which is absent for PL. The proposed model satisfactorily describes the experimental data on the effect of solvent deuteration on the SL intensity. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1074–1078, July, 2006.