Colloidal suspensions of EuCl2, EuBr2, and EuSO4 nanoparticles (<50 nm) in dodecane and EuSO4 in 70% H2SO4 were synthesized. Moving single-bubble sonoluminescence (m-SBSL) spectra were obtained for a bubble performing radial oscillations in these suspensions and translational motions at the antinode of a standing ultrasonic wave with a frequency of about 27 kHz. In these spectra (at a spectral resolution of 10 nm), the sono-excited luminescence bands of the Eu2+ ion were detected for the first time, coinciding in the shape and position of the maxima (404, 413, and 377 nm for EuCl2, EuBr2, and EuSO4, respectively) with the bands of Eu2+ located in a crystalline environment in the photoluminescence spectra of nanoparticles of europium salts in suspensions. The detected sonoluminescence of Eu2+ arises due to the injection of nanoparticles into a bubble deformed during motion and excitation of a lanthanide ion at the periphery of the bubble volume during collisions of nanoparticles with charged particles, mainly electrons, coming from a hot nonequilibrium plasma, which periodically arises during bubble compression. Evidence for the excitation of the europium ion in the bubble is the absence of its luminescence bands in the SBSL spectra of the translationally immobile bubble, in which nanoparticles are unlikely to enter. The nanoparticles that enter the bubble also undergo decomposition in the plasma into fragments, in particular, with the formation of Eu, Eu+ in the excited state. The atomic lines of these fragments were recorded for the first time in the m-SBSL spectrum with a resolution of 1 nm for a suspension of EuSO4 nanoparticles in 70% H2SO4. The resulting m-SBSL spectra will add to the library of characteristic spectra of objects of sonoluminescent spectroscopic analysis and will make it possible to identify and determine the content of Eu or Eu2+ in these objects.

中文翻译：

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铕(II)盐纳米颗粒胶体悬浮液的单泡声致发光。

合成了 EuCl2、EuBr2 和 EuSO4 纳米颗粒（<50 nm）在十二烷中的胶体悬浮液以及 EuSO4 在 70% H2SO4 中的胶体悬浮液。获得了气泡在这些悬浮液中进行径向振荡以及在频率约为 27 kHz 的超声波波腹处进行平移运动的移动单气泡声致发光 (m-SBSL) 光谱。在这些光谱中（光谱分辨率为10 nm），首次检测到Eu2+离子的声激发发光带，与最大值的形状和位置一致（EuCl2为404、413和377 nm，分别为 EuBr2 和 EuSO4），在悬浮液中铕盐纳米粒子的光致发光光谱中，Eu2+ 的谱带位于晶体环境中。检测到的 Eu2+ 声致发光是由于将纳米粒子注入到运动过程中变形的气泡中而产生的，并且在纳米粒子与来自热非平衡等离子体的带电粒子（主要是电子）碰撞期间激发了气泡体积外围的镧系离子，这在气泡压缩过程中周期性地出现。气泡中铕离子被激发的证据是，在平移不动的气泡的 SBSL 光谱中不存在其发光带，纳米粒子不太可能进入其中。进入气泡的纳米粒子也会在等离子体中分解成碎片，特别是在激发态形成Eu、Eu+。这些碎片的原子谱线首次在 m-SBSL 光谱中以 1 nm 的分辨率记录了 EuSO4 纳米粒子在 70% H2SO4 中的悬浮液。所得的 m-SBSL 光谱将添加到声致发光光谱分析物体的特征光谱库中，并使识别和测定这些物体中 Eu 或 Eu2+ 的含量成为可能。