Department of Chemistry, Princeton University, Princeton, NJ 08544, USA.
Mechanical and Aerospace Engineering Department, Princeton University, Princeton, NJ 08544, USA.
Sci Rep. 2017 Jan 10;7:40230. doi: 10.1038/srep40230.
We report a theoretical analysis showing that Rayleigh scattering could be used to monitor the growth of nanoparticles under arc discharge conditions. We compute the Rayleigh scattering cross sections of the nanoparticles by combining light scattering theory for gas-particle mixtures with calculations of the dynamic electronic polarizability of the nanoparticles. We find that the resolution of the Rayleigh scattering probe is adequate to detect nanoparticles as small as C at the expected concentrations of synthesis conditions in the arc periphery. Larger asymmetric nanoparticles would yield brighter signals, making possible to follow the evolution of the growing nanoparticle population from the evolution of the scattered intensity. Observable spectral features include characteristic resonant behaviour, shape-dependent depolarization ratio, and mass-dependent line shape. Direct observation of nanoparticles in the early stages of growth with unobtrusive laser probes should give insight on the particle formation mechanisms and may lead to better-controlled synthesis protocols.
我们报告了一项理论分析，表明瑞利散射可用于监测电弧放电条件下纳米颗粒的生长。我们通过将适用于气-粒混合物的光散射理论与纳米颗粒动态电子极化率的计算相结合，计算了纳米颗粒的瑞利散射截面。我们发现，瑞利散射探针的分辨率足以检测到在电弧边缘预期的合成条件下浓度下小至 C 的纳米颗粒。更大的非对称纳米颗粒将产生更亮的信号，从而可以根据散射强度的变化来跟踪生长的纳米颗粒群体的演变。可观察到的光谱特征包括特征共振行为、与形状相关的退偏振比以及与质量相关的谱线形状。使用无干扰的激光探针直接观察生长初期的纳米颗粒，应该可以深入了解颗粒形成机制，并可能导致更好的控制合成方案。
