抄録
Single-bubble sonoluminescence (SBSL) in aqueous sodium chrolide (NaCl), lithium chrolide (LiCl) and lithium bromide(LiBr) solutions ranging from 0 M to 5 M concentrations were studied. The SBSL intensity was increased with concentration in each solution, as expected. In LiBr solution, the intensity was higher than the other solutions. In our previous study, we found that the SBSL intensity increases in aqueous alkaline haide solutions, but we could not give any complete explanation for the result because we also have to take into account effects of increase in surface tension, viscosity, density and so on. The present result may indicate that alkali salt reduces vapor pressure in an oscillationg bubble. It is known that larger halide anions in alkali salt solutions prevent water molecules from diffusing. Therefore the vapor pressure is reduced in water and air interface. Previous SBSL studies show that the SBSL intensity increases for lower vapor pressure in the bubble. We conclude that the Br anion, which is larger than Cl anion, reduced the vapor pressure more in the bubble, and enhanced the SBSL intensity.
