3D Electron crystallography: Real space reconstruction and reciprocal space tomography
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Electron crystallography is an important technique for studying micro- and nano-sized materials. It has two important advantages over X-ray crystallography for structural studies: 1) crystals millions of times smaller than those needed for X-ray diffraction can be studied; 2) it is possible to; focus the electrons to form an image. The local atomic arrangement can be seen directly by high-resolution transmission electron microscopy (HRTEM). The crystallographic structure factor phases, which are lost in recording diffraction patterns, are present in HRTEM images and can be determined experimentally. The main disadvantages of electron crystallography compared to X-ray diffraction are that the data are difficult to collect, often incomplete and suffer from dynamic scattering. New methods need to be developed to overcome these problems. In this work, structure determination of several unique and complex porous materials including zeolites and mesoporous silica is demonstrated. None of the structures of these materials could be solved by X-ray crystallography. New techniques are also developed in order to overcome the disadvantages of electron crystallography. The new techniques include a digital sampling method for collecting precession electron diffraction data and a rotation method for automatic collection of complete 3D electron diffraction data. A number of practical issues concerning data collection and data processing are described and the data quality is analysed.
Place, publisher, year, edition, pages
Stockholm: Department of Materials and Environmental Chemistry (MMK), Stockholm University , 2010. , 72 p.
Electron crystallography, Electron microscopy, Porous materials
Research subject Structural Chemistry
IdentifiersURN: urn:nbn:se:su:diva-39034ISBN: 978-91-7447-044-4OAI: oai:DiVA.org:su-39034DiVA: diva2:318051
2010-06-08, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 16 B, Stockholm, 10:00 (English)
Dorset, Douglas L., Dr
Zou, Xiaodong, Professor
At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Submitted.2010-05-172010-05-062010-05-14Bibliographically approved
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