Single-bubble sonoluminescence

Abstract

To gain insight into the mechanism by which nonvolatile species enter a cavitating bubble’s core and emit light, sulfuric acid (H2SO4) and a surfactant sodium dodecyl sulfate (SDS) were explored for studies of single-bubble sonoluminescence (SBSL) to test the heated shell model of nonvolatile vaporization. It was found that the surfactant SDS underwent a chemical reaction, entered the bubble’s core and emitted light as evidenced by the presence of C2 emission bands in the spectra; however, the mechanism could not be clearly determined due to translational bubble motion, which could inject droplets of solution into the bubble’s core. Through the use of dual frequencies to stabilize the translational bubble motion, some evidence was shown against the heated shell model when the C2 emission bands remained present without reduced intensity in the spectra after the translational bubble motion had been greatly reduced.