The Chemical History of a Bubble

Autor: Hangxun Xu, Kenneth S. Suslick, David J. Flannigan, Stephen D. Hopkins, Nathan C. Eddingsaas
Rok vydání: 2018
Předmět:
Zdroj: Accounts of Chemical Research. 51:2169-2178
ISSN: 1520-4898
0001-4842
DOI: 10.1021/acs.accounts.8b00088
Popis: Acoustic cavitation (the growth, oscillation, and rapid collapse of bubbles in a liquid) occurs in all liquids irradiated with sufficient intensity of sound or ultrasound. The collapse of such bubbles creates local heating and provides a unique source of energy for driving chemical reactions. In addition to sonochemical bond scission and formation, cavitation also induces light emission in many liquids. This phenomenon of sonoluminescence (SL) has captured the imagination of many researchers since it was first observed 85 years ago. SL provides a direct probe of cavitation events and has provided most of our understanding of the conditions created inside collapsing bubbles. Spectroscopic analyses of SL from single acoustically levitated bubbles as well as from clouds of bubbles have revealed molecular, atomic, and ionic line and band emission riding atop an underlying continuum arising from radiative plasma processes. Application of spectrometric methods of pyrometry and plasma diagnostics to these spectra has permitted quantitative measurement of the intracavity conditions: relative peak intensities for temperature measurements, peak shifts and broadening for pressures, and peak asymmetries for plasma electron densities. The studies discussed herein have revealed that extraordinary conditions are generated inside the collapsing bubbles in ordinary room-temperature liquids: observable temperatures exceeding 15 000 K (i.e., three times the surface temperature of our sun), pressures of well over 1000 bar (more than the pressure at the bottom of the Mariana Trench), and heating and cooling rates in excess of 10
Databáze: OpenAIRE
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