Multibubble sonoluminescence in aqueous salt solutions

摘要

The sonoluminescence from aqueous solutions containing various salts in the concentration range of 0 to 7 M has been examined using 3.5 ms pulses of 515 kHz ultrasound. In almost all cases the sonoluminescence intensity recorded increased withincreasing salt level until a critical concentration (in the range of 1-2 M) was reached. At salt levels above the critical concentration the signal intensity decreased sharply with Increasing salt concentration. It is not possible to satisfactorilyaccount for the trends in terms of changes in solution viscosity, rate of bubble coalescence, water vapour pressure, air/water interfacial tension or ionic strength. However, a good correlation of the increase in the signal with the extent of gassolubilisation in the solutions with charging salt concentration was observed. Possible reasons for the signal increase with the addition of salts and the marked decrease at high salt concentrations are discussed.