Deumer Jérôme, Pauw Brian R, Marguet Sylvie, Skroblin Dieter, Taché Olivier, Krumrey Michael, Gollwitzer Christian
Physikalisch-Technische Bundesanstalt (PTB), Abbestraße 2-12, 10587 Berlin, Germany.
Federal Institute for Materials Research and Testing (BAM), Unter den Eichen 87, 12205 Berlin, Germany.
J Appl Crystallogr. 2022 Jul 15;55(Pt 4):993-1001. doi: 10.1107/S160057672200499X. eCollection 2022 Aug 1.
A versatile software package in the form of a Python extension, named (computing Debye's scattering formula for extraordinary form factors), is proposed to calculate approximate scattering profiles of arbitrarily shaped nanoparticles for small-angle X-ray scattering (SAXS). generates a quasi-randomly distributed point cloud in the desired particle shape and then applies the open-source software for efficient evaluation of Debye's scattering formula to calculate the SAXS pattern (https://github.com/j-from-b/CDEF). If self-correlation of the scattering signal is not omitted, the quasi-random distribution provides faster convergence compared with a true-random distribution of the scatterers, especially at higher momentum transfer. The usage of the software is demonstrated for the evaluation of scattering data of Au nanocubes with rounded edges, which were measured at the four-crystal monochromator beamline of PTB at the synchrotron radiation facility BESSY II in Berlin. The implementation is fast enough to run on a single desktop computer and perform model fits within minutes. The accuracy of the method was analyzed by comparison with analytically known form factors and verified with another implementation, the , based on a similar principle with fewer approximations. Additionally, the coupled to allows one to retrieve information on the uncertainty of the size distribution using a Monte Carlo uncertainty estimation algorithm.
提出了一个以Python扩展形式存在的通用软件包，名为（计算非寻常形状因子的德拜散射公式），用于计算任意形状纳米颗粒在小角X射线散射（SAXS）下的近似散射轮廓。该软件包在所需的颗粒形状中生成准随机分布的点云，然后应用开源软件来高效评估德拜散射公式以计算SAXS图案（https://github.com/j-from-b/CDEF）。如果不忽略散射信号的自相关，与散射体的真随机分布相比，准随机分布能提供更快的收敛速度，特别是在较高动量转移时。展示了该软件在评估带有圆边的金纳米立方体散射数据中的应用，这些数据是在柏林同步辐射设施BESSY II的PTB四晶体单色仪光束线上测量的。该软件的实现速度足够快，可以在单台台式计算机上运行，并在几分钟内完成模型拟合。通过与解析已知的形状因子进行比较分析了该方法的准确性，并使用基于类似原理且近似较少的另一种实现方法——进行了验证。此外，与耦合的该软件包允许使用蒙特卡罗不确定性估计算法来检索关于尺寸分布不确定性的信息。
