Sonoluminescence (SL) spectra were collected from water doped with several organic liquids (pentane, cyclohexane, benzene, ethanol, tert-butyl alcohol, glycerol, carbon tetrachloride, carbon disulfide, and acetone) at low concentrations. Most of the organic substances showed emission from C2 and an overall decrease in the intensity relative to SL from pure water. This decrease was due to the consumption by the organic substrates of hydroxyl radicals and other incipient emitting species produced during sonolysis. Small concentrations of CS2 did not lead to emission from C2 but caused an increase in SL intensity across the spectral window, due to its own fluorescence. CCl4 did not change the intensity of water sonoluminescence but exhibited C2 emission, indicating that the dissociation of CCl4 inside the cavitation bubble was independent of the products of water sonolysis. Benzene showed the greatest C2 emission. The emission of excited-state C2 arising from the sonication of benzene/water mixtures at 20 kHz was used to determine an effective emission temperature during cavitation in water. Interband analysis of the two C2 bands seen during irradation of water/benzene mixtures at 278 K under Ar showed an emission temperature of 4300 ± 200 K.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry