Abstract
A 2-beam model is used to simulate precession electron diffraction (PED) intensities. It is shown that this model can be inverted with minimal knowledge of the underlying crystal structure, permitting structure factor amplitudes to be deduced directly from measured intensities within the 2-beam approximation. This approach may be used in conjunction with direct methods to obtain correct, kinematically interpretable structure indications for data sets from relatively thin crystals (less than approximately 400 Å), and an experimental example based on (Ga,In)2SnO5 is presented. The failure of this approach at large thickness is illustrated by an additional data set for MFI zeolite. The 2-beam approximation provides a simple model for PED intensities, and inversion using this model shows advantages over a kinematical approximation. It is however too rough approximation to be of general use and ultimately it is to be hoped that more accurate models with similar ease of use can be derived to treat PED data.
Original language | English (US) |
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Pages (from-to) | 543-550 |
Number of pages | 8 |
Journal | Ultramicroscopy |
Volume | 107 |
Issue number | 6-7 |
DOIs | |
State | Published - Jun 2007 |
Funding
The authors would like to acknowledge the support of UOP LLC for use of microscopes and support of precession instrumentation. Additional funding was provided by STCS, the US Department of Energy (Grant no. DE-FG02-03ER 15457), as well as Fannie and John Hertz Foundation (CSO).
Keywords
- Electron crystallography
- Precession electron diffraction
- Zeolite
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Instrumentation
- Atomic and Molecular Physics, and Optics