Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany.
J Phys Chem A. 2011 Jan 20;115(2):136-40. doi: 10.1021/jp1083339. Epub 2010 Dec 17.
Spectroscopic studies of single-bubble sonoluminescence (SBSL) in water and aqueous sodium chloride solutions with a defined concentration of argon were performed as a function of the driving acoustic pressure. The broad-band continuum ranging from 200 to 700 nm is characterized by fits using Planck's law of blackbody radiation. The obtained blackbody temperatures are in the range of 10(4) K and are revealed to be independent of the presence of a salt and the acoustic pressure, whereas the SL intensity increases by a factor of more than 10 within the studied acoustic pressure range. The different trends followed by SL intensity and blackbody temperatures question the blackbody model. In solutions with 70 mbar of argon, line emissions of OH(•) radicals and Na* are observed. The shape of the OH(•) radical emission spectrum is very similar to that in MBSL spectra, indicating the strong similarity of intrabubble conditions. An increase of the acoustic pressure causes the continuum to overlap the lines until they become indistinguishable. The emission line of Na* in NaCl is observed only at high NaCl concentrations. When sodium dodecylsulfate is used a pronounced Na* line is already observed in a 1 mM solution thanks to enrichment of sodium ions at the interface. The results presented in this work reveal the strong similarity of SBSL and MBSL under certain experimental conditions.
在水中和含有特定浓度氩气的氯化钠水溶液中进行了单泡声致发光（SBSL）的光谱研究，作为驱动声压的函数。从 200nm 到 700nm 的宽带连续谱通过黑体辐射的普朗克定律拟合来进行表征。获得的黑体温度在 10^4 K 范围内，并且被发现与盐的存在和声压无关，而在研究的声压范围内，SL 强度增加了超过 10 倍。SL 强度和黑体温度所遵循的不同趋势对黑体模型提出了质疑。在含有 70 毫巴氩气的溶液中，观察到 OH(•)自由基和 Na的线发射。OH(•)自由基发射光谱的形状与 MBSL 光谱非常相似，表明气泡内条件非常相似。随着声压的增加，连续谱会与谱线重叠，直到它们变得无法区分。只有在高 NaCl 浓度下才能观察到 NaCl 中的 Na发射线。当使用十二烷基硫酸钠时，由于界面处钠离子的富集，即使在 1mM 的溶液中也可以观察到明显的 Na*谱线。本工作所呈现的结果揭示了在某些实验条件下 SBSL 和 MBSL 的强烈相似性。
