Weirich Thomas E
Gemeinschaftslabor für Elektronenmikroskopie (GFE) RWTH Aachen University Ahornstrasse 55 52074Aachen Germany.
J Appl Crystallogr. 2024 Nov 26;57(Pt 6):2017-2029. doi: 10.1107/S1600576724010215. eCollection 2024 Dec 1.
As an extension to previous work, the macro script (ratio-method pattern indexing) has been developed to allow instant indexing of calibrated and uncalibrated zone axis aligned electron diffraction patterns of cubic lattices using the ratio principle. The program can be used to index zone axis aligned selected-area electron diffraction patterns, nanobeam electron diffraction patterns, transmission electron microscopy (TEM) Kikuchi patterns and even fast Fourier transforms of high-resolution (scanning) TEM images. The program allows the user to quickly assess whether the material under investigation belongs to the cubic crystal system, is pseudo-cubic or is not cubic at all by adjusting the boundary parameters and allowed errors for lattice indexing. The software also allows one to distinguish between the , and Bravais lattices for certain zone axis directions. For calibrated diffraction patterns, the lattice parameters can be obtained, allowing verification of the material under investigation or phase identification in connection with a structural database. In addition, the program can be employed for determination or verification of the used instrument's camera constant when reference materials are used. Therefore, it is a convenient tool for on-site crystallographic analysis in TEM laboratories.
作为先前工作的扩展,已开发出宏脚本(比率法图案索引),以便使用比率原理对立方晶格的校准和未校准区域轴对齐电子衍射图案进行即时索引。该程序可用于索引区域轴对齐的选区电子衍射图案、纳米束电子衍射图案、透射电子显微镜(TEM)菊池线图案,甚至高分辨率(扫描)TEM图像的快速傅里叶变换。通过调整晶格索引的边界参数和允许误差,该程序允许用户快速评估所研究的材料是否属于立方晶体系统、是否为假立方或根本不是立方。该软件还允许在某些区域轴方向上区分简单立方、体心立方和面心立方布拉菲晶格。对于校准后的衍射图案,可以获得晶格参数,从而可以结合结构数据库对所研究的材料进行验证或相鉴定。此外,当使用参考材料时,该程序可用于确定或验证所用仪器的相机常数。因此,它是TEM实验室现场晶体学分析的便捷工具。