Sonoluminescence from cavitating clouds of bubbles (multi-bubble sonoluminescence MBSL) in room temperature liquids closely resembles flame emission. Effective emission temperatures were obtained for MBSL from excited state metal atom emission. The effective transient conditions formed during cavitation of bubble clouds under Ar in low volatility solvents were ∼ 5000 K, 500 atm, which implied heating and cooling rates in excess of 110 K/sec. Sonoluminescence spectra were collected from water doped with several organic liquids at low concentrations. Benzene showed the strongest C2 emission. Interband analysis of C2 bands observed during irradiation of water/benzene mixtures at 278 K under argon indicated an emission temperature of 4300 K. Chemical reactions within collapsing bubbles were a major factor in determining and limiting the conditions reached during cavitation. Support for this was observed in the insensitivity of the temperature of MBSL to the thermal conductivity of the dissolved gas. Experiments on silicone oil revealed similar behavior. The results were consistent with the expected effects of sonolysis: more of the energy of compression is consumed by bond dissociations under Xe than under He. Such reactions convert larger molecules, e.g., octanol, into many small gas molecules, e.g., H2, CH4, C2H2, and CO2. This is an abstract of a paper presented at the 221st ACS National Meeting (San Diego, CA 4/1-5/2001).
|Original language||English (US)|
|Number of pages||2|
|Journal||ACS Division of Environmental Chemistry, Preprints|
|State||Published - 2001|
ASJC Scopus subject areas
- Chemical Engineering(all)