Scardi P, Gelisio L
University of Trento, Department of Civil, Environmental and Mechanical Engineering, Trento, 38123, Italy.
Sci Rep. 2016 Feb 26;6:22221. doi: 10.1038/srep22221.
One hundred years after the original formulation by Petrus J.W. Debije (aka Peter Debye), the Debye Scattering Equation (DSE) is still the most accurate expression to model the diffraction pattern from nanoparticle systems. A major limitation in the original form of the DSE is that it refers to a static domain, so that including thermal disorder usually requires rescaling the equation by a Debye-Waller thermal factor. The last is taken from the traditional diffraction theory developed in Reciprocal Space (RS), which is opposed to the atomistic paradigm of the DSE, usually referred to as Direct Space (DS) approach. Besides being a hybrid of DS and RS expressions, rescaling the DSE by the Debye-Waller factor is an approximation which completely misses the contribution of Temperature Diffuse Scattering (TDS). The present work proposes a solution to include thermal effects coherently with the atomistic approach of the DSE. A deeper insight into the vibrational dynamics of nanostructured materials can be obtained with few changes with respect to the standard formulation of the DSE, providing information on the correlated displacement of vibrating atoms.
在彼得鲁斯·J.W. 德拜（又名彼得·德拜）最初提出该方程一百年后，德拜散射方程（DSE）仍是模拟纳米颗粒系统衍射图案最精确的表达式。DSE原始形式的一个主要局限在于它涉及静态域，因此纳入热无序通常需要用德拜 - 瓦勒热因子对方程进行重新缩放。后者取自倒易空间（RS）中发展的传统衍射理论，这与DSE的原子论范式相反，后者通常被称为直接空间（DS）方法。除了是DS和RS表达式的混合体之外，用德拜 - 瓦勒因子对DSE进行重新缩放是一种近似，它完全忽略了温度漫散射（TDS）的贡献。本工作提出了一种与DSE的原子论方法一致地纳入热效应的解决方案。相对于DSE的标准公式只需做少许改变，就能更深入地洞察纳米结构材料的振动动力学，从而提供有关振动原子相关位移的信息。
