Sonoluminescence bubbles

Holzfuss J, Riiggeberg M, Billo A (1998) Shock wave emissions of a sonoluminescing bubble. Phys Rev Lett 81 5434-5437... 

Lee J, Ashokkumar M, Kentish S, Grieser F (2005) Determination of the size distribution of sonoluminescence bubbles in apulsed acoustic field. J Am Chem Soc 127 16810-16811... 

The almost featureless spectrum at 1.0 MHz is reminiscent of the result by Matula et al. [35], i.e., the SBSL spectrum from NaCl solution indicated only continuum emission with no atomic lines. Sonoluminescing bubbles at higher frequencies are smaller and interact less with surrounding bubbles. These factors may explain why the MBSL spectrum at 1 MHz is similar to that of SBSL. 

Multiple-Bubble Sonoluminescence. The sonoluminescence of aqueous solutions has been often examined over the past thirty years. The spectmm of MBSL in water consists of a peak at 310 nm and a broad continuum throughout the visible region. An intensive study of aqueous MBSL was conducted by VerraH and Sehgal (35). The emission at 310 nm is from excited-state OH, but the continuum is difficult to interpret. MBSL from aqueous and alcohol solutions of many metal salts have been reported and are characterized by emission from metal atom excited states (36). 

Single-Bubble Sonoluminescence. The spectra of MBSL and SBSL are dramatically different. MBSL is generally dominated by atomic and molecular emission lines, but SBSL is an essentially featureless emission that iacreases with decreasiag wavelength. For example, an aqueous solution of NaCl shows evidence of excited states of both OH- and Na ia the MBSL spectmm however, the SBSL spectmm of an identical solution shows no evidence of either of these peaks (30). Similady, the MBSL spectmm falls off at low wavelengths, while the SBSL spectmm continues to rise, at least for bubbles containing most noble gases (38). 

The phenomenon of acoustic cavitation results in an enormous concentration of energy. If one considers the energy density in an acoustic field that produces cavitation and that in the coUapsed cavitation bubble, there is an amplification factor of over eleven orders of magnitude. The enormous local temperatures and pressures so created result in phenomena such as sonochemistry and sonoluminescence and provide a unique means for fundamental studies of chemistry and physics under extreme conditions. A diverse set of apphcations of ultrasound to enhancing chemical reactivity has been explored, with important apphcations in mixed-phase synthesis, materials chemistry, and biomedical uses. 

There are two types in acoustic cavitation. One is transient cavitation and the other is stable cavitation [14, 15]. There are two definitions in transient cavitation. One is that the lifetime of a bubble is relatively short such as one or a few acoustic cycles as a bubble is fragmented into daughter bubbles due to its shape instability. The other is that bubbles are active in light emission (sonoluminescence (SL)) or chemical reactions (sonochemical reactions). Accordingly, there are two definitions in stable cavitation. One is that bubbles are shape stable and have a long lifetime. The other is that bubbles are inactive in SL and chemical reactions. There exist... 

Experimentally, Brotchie et al. [55] have shown that the range of ambient radius of sonoluminescing (SL) bubbles in which the temperature is relatively high... 

In some literature, there is a description that a bubble with linear resonance radius is active in sonoluminescence and sonochemical reactions. However, as already noted, bubble pulsation is intrinsically nonlinear for active bubbles. Thus, the concept of the linear resonance is not applicable to active bubbles (That is only applicable to a linearly pulsating bubble under very weak ultrasound such as 0.1 bar in pressure amplitude). Furthermore, a bubble with the linear resonance radius can be inactive in sonoluminescence and sonochemical reactions [39]. In Fig. 1.8, the calculated expansion ratio (/ max / Rq, where f max is the maximum radius and R0 is the ambient radius of a bubble) is shown as a function of the ambient radius (Ro) for various acoustic amplitudes at 300 kHz [39]. It is seen that the ambient radius for the peak in the expansion ratio decreases as the acoustic pressure amplitude increases. While the linear resonance radius is 11 pm at 300 kHz, the ambient radius for the peak at 3 bar in pressure amplitude is about 0.4 pm. Even at the pressure amplitude of 0.5 bar, it is about 5 pm, which is much smaller than the linear resonance radius. 

Fig. 1.9 The calculated results as a function of ambient radius at 300 kHz and 3 bar in ultrasonic frequency and pressure amplitude, respectively. The horizontal axis is in logarithmic scale, (a) The peak temperature (solid) and the molar fraction of water vapor (dash dotted) inside a bubble at the end of the bubble collapse, (b) The rate of production of oxidants with the logarithmic vertical axis. Reprinted with permission from Yasui K, Tuziuti T, Lee J, Kozuka T, Towata A, Iida Y (2008) The range of ambient radius for an active bubble in sonoluminescence and sonochemical reactions. J Chem Phys 128 184705. Copyright 2008, American Institute of Physics...

Suslick KS, Flannigan DJ (2008) Inside a collapsing bubble Sonoluminescence and the conditions during cavitation. Ann Rev Phys Chem 59 659-683... 

Weninger KR, Camara CG, Putterman SJ (2001) Observation of bubble dynamics within luminescent cavitation clouds sonoluminescence at the nano-scale. Phys Rev E 63 016310... 

Guan J, Matula TJ (2003) Time scales for quenching single-bubble sonoluminescence in the presence of alcohols. J Phys Chem 107 8917-8921... 

Matula TJ, Cordry SM, Roy RA, Crum LA (1997) Bjerknes force and bubble levitation under single-bubble sonoluminescence conditions. J Acoust Soc Am 102 1522-1527... 

Yasui K, Tuziuti T, Lee J, Kozuka T, Towata A, Iida Y (2008) The range of ambient radius for an active bubble in sonoluminescence and sonochemical reactions. J Chem Phys 128 184705... 

Brenner MP, Hilgenfeldt S, Lohse D (2002) Single-bubble sonoluminescence. Rev Mod Phys 74 425 184... 

Yasui K (1999) Mechanism of single-bubble sonoluminescence. Phys Rev E 60 1754—1758... 

Yasui K (1996) Variation of liquid temperature at bubble wall near the sonoluminescence threshold. J Phys Soc Jpn 65 2830-2840... 

Putterman SJ, Weninger KR (2000) Sonoluminescence how bubbles turn sound into light. Annu Rev Fluid Mech 32 445 -76... 

Abstract Sonoluminescence from alkali-metal salt solutions reveals excited state alkali - metal atom emission which exhibits asymmetrically-broadened lines. The location of the emission site is of interest as well as how nonvolatile ions are reduced and electronically excited. This chapter reviews sonoluminescence studies on alkali-metal atom emission in various environments. We focus on the emission mechanism does the emission occur in the gas phase within bubbles or in heated fluid at the bubble/liquid interface Many studies support the gas phase origin. The transfer of nonvolatile ions into bubbles is suggested to occur by means of liquid droplets, which are injected into bubbles during nonspherical bubble oscillation, bubble coalescence and/or bubble fragmentation. The line width of the alkali-metal atom emission may provide the relative density of gas at bubble collapse under the assumption of the gas phase origin. 

Hayashi Y, Choi P-K (2006) Effects of alcohols on multi-bubble sonoluminescence spectra. Ultrasonics 44 e421-e423... 

Ashokkumar M, Crum LA, Frenley CA, Grieser F, Matula TJ, McNamara WB III, Suslick KS (2000) Effect of solutes on single-bubble sonoluminescence in water. J Phys Chem A 104 8462-8465... 

Matula TJ, Roy RA, Mourad PD (1995) Comparison of multibubble and single-bubble sonoluminescence spectra. Phys Rev Lett 75 2602-2605... 

Flannigan DJ, Suslick KS (2007) Emission from electronically excited metal atoms during single-bubble sonoluminescence. Phys Rev Lett 99 134301... 

Didenko YT, McNamara WB, Suslick KS (2000) Molecular emission from single-bubble sonoluminescence. Nature 407 877-879... 

McNamara WBI, Didenko YT, Suslick KS (1999) Sonoluminescence temperatures during multi-bubble cavitation. Nature 401 772-775... 

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