We are excited to host Dr. Hongyi Xu as a speaker at Eldico’s next webinar the 2nd of March. He is not only a valuable and distinguished member of our scientific advisory board but also a principal investigator at the Department of Materials and Environmental Chemistry at Stockholm University, where ELDICO’s electron diffractometer, ELDICO ED-1, will be installed soon. As Dr. Xu is responsible to further develop and apply electron crystallography methods, we used this opportunity to learn more from him about the experiments he plans to conduct at the Stockholm lab and ask him about the anticipated advantages of a dedicated electron diffractometer, like the ELDICO ED-1.
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How does the design of ELDICO ED-1 differ to the electron capabilities currently available at Stockholm and where are ED-1’s benefits? What type of experiments are you planning to perform on ELDICOs electron diffractometer?
ED-1 is a dedicated electron diffractometer which is ideal for high throughput crystal structure characterization by 3D-ED. This instrument will be unique in any lab, providing researchers with the capability to study crystal structures from sub-micrometer crystals. The large sample chamber (also called octagon) provides superior opportunities for attaching add-ons to perform advanced experiments.
We will mainly use ED-1 for structural characterization of porous materials and pharmaceutical compounds. We will also develop new electron diffraction applications on the ED-1, such as 3D ED data without missing wedge, in-situ crystallography and so on. I also expect new experimental approaches evolving from the flexibility and the versatility which lay in the constructive principles of the ELDICO ED-1.
- Which advantages do you expect from performing experiments on ELDICO ED-1?
I expect to be able to obtain more accurate unit cell parameters using ELDICO ED-1. The implementation of a ‘real’ goniometer on the ED-1 with a sphere of confusion of 500 nm or even less makes it possible to acquire accurate unit cell parameters. The removal of the projection lens means that distortions caused by electromagnetic lenses after the sample are removed. Hence, unit cell accuracy can also be improved.
I also expect to be able to collect data of higher completeness, as there is no rotation limit for ED-1. This is because the ED-1 has a goniometer that can rotate freely without having to worry about the sample holder hitting the pole piece when working with a TEM. We can then be creative with sample preparation to achieve high tilt range and high completeness.
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What developments in the application and capabilities of ED-1 do you want to see in the future?
We are looking forward to ELDICO developing new software based on our experiences to realize high throughput structure determination and phase analysis on ED-1. This will include fast and simple sample loading, survey of the grid, automated crystal identification, automatic alignment and data collection, data management and on-the-fly data processing. The design of the octagon provides opportunities for designing a more efficient sample exchange system. The low-dose STEM imaging provides good contrast for crystal picking. The goniometer with easy crystal centering makes it easier to implement automated data collection protocol. Fixing the detector distance/reciprocal pixel size may have some negative effects, but it also means that data processing parameters do not have to be changed for on-the-fly processing.
