Plana-Ruiz S, Krysiak Y, Portillo J, Alig E, Estradé S, Peiró F, Kolb U
Institut für Angewandte Geowissenschaften, Technische Universität Darmstadt, Petersenstrasse 23, 64287 Darmstadt, Germany; LENS, MIND/IN2UB, Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Catalonia; Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, 08028 Barcelona, Catalonia, Spain.
Institut für Angewandte Geowissenschaften, Technische Universität Darmstadt, Petersenstrasse 23, 64287 Darmstadt, Germany.
Ultramicroscopy. 2020 Apr;211:112951. doi: 10.1016/j.ultramic.2020.112951. Epub 2020 Jan 28.
Electron crystallography has focused in the last few years on the analyses of microcrystals, mainly organic compounds, triggered by recent publications on acquisition methods based on direct detection cameras and continuous stage tilting. However, the main capability of a transmission electron microscope is the access to features at the nanometre scale. In this context, a new acquisition method, called fast and automated diffraction tomography (Fast-ADT), has been developed in form of a general application in order to get the most of the diffraction space from a TEM. It consists of two subsequent tilt scans of the goniometric stage; one to obtain a crystal tracking file and a second one to acquire an electron diffraction tomography. This setup has been implemented on both TEM and STEM modes of the microscope, thus it can be installed on any TEM regardless of the availability of a scanning unit. BaSO crystals have been measured to demonstrate the validity of the technique for structure determination and refinement. A recently solved layered silicate, RUB-5, has been used to prove the method advantages for fine identification of disorder details. Last, a new polymorph of a DRED1 organic molecule has been solved ab initio and refined by X-ray powder diffraction to show the full application of the presented method.
在过去几年中，电子晶体学主要聚焦于对微晶（主要是有机化合物）的分析，这是由近期关于基于直接检测相机和连续样品台倾斜的采集方法的出版物所引发的。然而，透射电子显微镜的主要功能是能够观察纳米尺度的特征。在此背景下，一种名为快速自动衍射断层扫描（Fast-ADT）的新采集方法已被开发成一种通用应用程序，以便充分利用透射电子显微镜的衍射空间。它包括对测角台进行两次连续的倾斜扫描；一次用于获取晶体跟踪文件，另一次用于采集电子衍射断层扫描数据。此设置已在显微镜的透射电子显微镜（TEM）和扫描透射电子显微镜（STEM）模式上实现，因此它可以安装在任何透射电子显微镜上，而无需考虑扫描单元是否可用。已对硫酸钡（BaSO）晶体进行测量，以证明该技术用于结构测定和精修的有效性。最近解析出结构的层状硅酸盐RUB-5已被用于证明该方法在精细识别无序细节方面的优势。最后，通过从头计算解析出一种DRED1有机分子的新多晶型物，并通过X射线粉末衍射进行精修，以展示所提出方法的全面应用。
