报告题目：3D structure determination of nano-sized crystals by electron crystallography – new methods and applications
报告人：Prof. Xiaodong Zou（邹晓冬）
报告时间：2012年10月25日（周四）14:00-16:00
报告地点：电镜中心会议室（教十一125室）
邀请人：张 泽院士
报告摘要：
Electron crystallography is an important technique complement to X-ray crystallography for structure determination. There are two main advantages of structure determinations by electron crystallography compared to X-ray diffraction: 1) crystals millions times smaller than what is needed for X-ray diffraction can be studied and 2) the phases of the crystallographic structure factors, which are lost in X-ray diffraction, are present in high resolution transmission electron microscopy images.
Here I will first introduce the research activity at the Berzelii Centre EXSELENT on Porous Materials. Then I will give a short introduction of electron crystallography and use several examples to demonstrate the methods for 3D structure determination by electron crystallography. I will introduce two new electron microscopy methods we recently developed: 3D rotation electron diffraction and through-focus structure projection reconstruction and their applications for determination of 3D structures of zeolites including the recently published zeolite catalyst ITQ-39. The methods are general and can be applied to any crystalline materials, where the crystals are too small or the structures too complicated to be solved by X-ray powder diffraction alone, especially for those crystals containing defects.
Figure 1. The 3D structure of one of the most complex zeolite catalyst IM-5 (Cmcm, a =14.2088 Å, b = 57.2368 Å, c =19.9940 Å) solved by combining HRTEM images from three main zone axes.The structure factor amplitudes and phases were extracted from the HRTEM images and combined to reconstruct the 3D electrostatic potential map.
