Dengo Nicola, Masciocchi Norberto, Cervellino Antonio, Guagliardi Antonietta, Bertolotti Federica
Dipartimento di Scienza e Alta Tecnologia & To.Sca.Lab, Università dell'Insubria, via Valleggio 11, 22100 Como, Italy.
Swiss Light Source, Paul Scherrer Institut, 5232 Villigen, Switzerland.
Nanomaterials (Basel). 2022 Apr 7;12(8):1252. doi: 10.3390/nano12081252.
Atomic- and nanometer-scale features of nanomaterials have a strong influence on their chemical and physical properties and a detailed description of these elements is a crucial step in their characterization. Total scattering methods, in real and reciprocal spaces, have been established as fundamental techniques to retrieve this information. Although the impact of microstructural features, such as defectiveness of different kinds, has been extensively studied in reciprocal space, disentangling these effects from size- and morphology-induced properties, upon downsizing, is not a trivial task. Additionally, once the experimental pattern is Fourier transformed to calculate the pair distribution function, the direct fingerprint of structural and microstructural features is severely lost and no modification of the histogram of interatomic distances derived therefrom is clearly discussed nor considered in the currently available protocols. Hereby, starting from atomistic models of a prototypical system (cadmium selenide), we simulate multiple effects on the atomic pair distribution function, obtained from reciprocal space patterns computed through the Debye scattering equation. Size and size dispersion effects, as well as different structures, morphologies, and their interplay with several kinds of planar defects, are explored, aiming at identifying the main (measurable and informative) fingerprints of these features on the total scattering pattern in real and reciprocal spaces, highlighting how, and how much, they become evident when comparing different cases. The results shown herein have general validity and, as such, can be further extended to other classes of nanomaterials.
纳米材料的原子和纳米尺度特征对其化学和物理性质有很大影响，详细描述这些元素是对其进行表征的关键步骤。实空间和倒易空间中的全散射方法已被确立为获取此类信息的基本技术。尽管诸如不同类型缺陷等微观结构特征的影响已在倒易空间中得到广泛研究，但在尺寸缩小时，将这些影响与尺寸和形态诱导的性质区分开来并非易事。此外，一旦将实验图案进行傅里叶变换以计算对分布函数，结构和微观结构特征的直接指纹就会严重丢失，并且在当前可用的协议中，对于由此得出的原子间距离直方图的修改既未进行清晰讨论也未予以考虑。在此，我们从一个典型系统（硒化镉）的原子模型出发，模拟了对通过德拜散射方程计算得到的倒易空间图案所获得的原子对分布函数的多种影响。我们探讨了尺寸和尺寸分散效应，以及不同的结构、形态及其与几种平面缺陷的相互作用，旨在识别这些特征在实空间和倒易空间的全散射图案上的主要（可测量且信息丰富的）指纹，突出在比较不同情况时它们如何以及在多大程度上变得明显。本文所示结果具有普遍有效性，因此可进一步扩展到其他类别的纳米材料。
