The role of vapour pressure in multibubble sonoluminescence from organic solvents

The action of high intensity cavitation on several liquid halocarbons (C2Cl4 CCl4, CHCl3, C2H2Br4) and other organic solvents (acetone, benzene and their mixtures) was investigated by recording multibubble sonoluminescence UV–Vis spectra over the temperature range between 246 and 298 K. The temperature induced variation of some thermophysical properties of the solvents Favours the interpretations of their role in determining the salient characteristics of the recorded spectra. We observed that high volatility does not necessarily quench sonoluminescence emission and that argon flow plays a key role in the appearance of radical emission lines. While for each investigated substance the intensity of C2∗ emission lines was clearly correlated to temperature, a comparative test between different halocarbons did not show a clear correlation with vapour pressure. Following recently reported results which evidenced the formation of dynamically differentiated populations of emitting bubbles in sulphuric acid, we performed MBSL experiments in liquid mixtures of halocarbons and sulphuric acid to investigate the correlation between the production of emitting species and the halocarbon volatility.

Research highlights
► Experimental evidence of plasma line emission from MBSL in highly volatile halocarbon.
► MBSL in organic solvents: emission lines intensity as function of liquid temperature.
► H2SO4 as a probe of liquid-liquid phase reactions at bubbles interface.