Methodology of structural electron crystallography


Structure analysis using electron diffraction data is a new field undergoing rapid development in all directions. In the group of electron crystallography, we address mainly two topics – software development for analysis of electron diffraction data and advancement of methods for structure determination from electron diffraction data using dynamical diffraction theory.


Software for data processing: PETS 2.0 

Raw electron diffraction data are a large set of individual diffraction patterns, which have to be processed by a computer. For XRD data processing, a wide selection of programs is available; however, for electron diffraction the selection of specialized software is limited. Therefore we are developping our own software called PETS, which is bridging this gap. PETS in its current version PETS 2.0 can process electron diffraction data from variable types of experimenal setups used in 3D electron diffraction and it also offers a few unique functions. PETS 2.0 is being used not only in FZU but also in other groups worldwide.

Structure determination using dynamical refinement, software Dyngo

Electrons interact with atoms in a crystal very strongly and therefore during their passing through the crystal they can be scattered more than once (multiple scattering). This phenomenon is described by dynamical diffraction theory. Dynamical theory is complex and therefore it is a common practice to replace it by less accurate but simpler kinematical theory. In our group, we focus on the development of software that uses the more complex but more accurate dynamical theory to determine the most correct model of atomic structure. The result of this research is software Dyngo and Jana2006 that allow more accurate and more sensitive crystallographic analysis compared to the programs that use the kinematical diffraction theory. This method allows using electron diffraction to acquire structure information with accuracy approaching that of X-ray diffraction methods but from the crystals with the size up to thousand times smaller.

Screenshot of PETS with diffraction

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