Fast electron diffraction tomography

Abstract

International audienceA fast and fully automatic procedure for collecting electron diffraction tomography data is presented. In the case of a very stable goniometer it is demonstrated how, by variation of the tilting speed and the CCD detector parameters, it is possible to obtain fully automatic precession-assisted electron diffraction tomography data collections, rotation electron diffraction tomography data collections or new integrated electron diffraction tomography data collections, in which the missing wedge of the reciprocal space between the patterns is recorded by longer exposures during the crystal tilt. It is shown how automatic data collection of limited tilt range can be used to determine the unit-cell parameters, while data of larger tilt range are suitable to solve the crystal structure ab initio with direct methods. The crystal structure of monoclinic MgMoO4 has been solved in this way as a test structure. In the case where the goniometer is not stable enough to guarantee a steady position of the crystal over large tilt ranges, an automatic method for tracking the crystal during continuous rotation of the sample is proposed

Ab initiostructure determination of nanocrystals of organic pharmaceutical compounds by electron diffraction at room temperature using a Timepix quantum area direct electron detector

“…It ensures good coverage of reciprocal space, it is experimentally less demanding than other approaches to data collection, it is optimal for radiationsensitive crystals and it allows straightforward data processing (Arndt & Wonacott, 1977). The rotation method has more recently been adopted in the field of electron crystallography (Nederlof et al, 2013;Nannenga et al, 2014;Gemmi et al, 2015), where it has become known as 'automated diffraction tomography' (ADT) (Kolb et al, 2007(Kolb et al, , 2008Mugnaioli et al, 2009). This and related methods like rotation electron diffraction (RED) (Zhang et al, 2010;Wan et al, 2013;Yun et al, 2015) have been used to solve crystal structures of beamsensitive compounds ab initio from three-dimensional ED data acquired at low electron dose from cryo-cooled samples.…”

A Porous Cobalt Tetraphosphonate Metal–Organic Framework: Accurate Structure and Guest Molecule Location Determined by Continuous‐Rotation Electron Diffraction

“…A complete data collection normally takes 1–2 hours. A much faster data collection has been achieved by continuously rotating the crystal during data collection . Unlike the stepwise RED (sRED), each ED frame in the continuous rotation electron diffraction (cRED) data records integrated intensities of reflections within a given rotation interval (Figure S6, Supporting Information).…”

Rapid Structure Determination of Microcrystalline Molecular Compounds Using Electron Diffraction

“…[26] Proper treatment of dynamic scattering effects can improve the level of detail of the structural model. [27,[32][33][34][35][36] In this study,w ec reated ap rototype of an electron diffractometer based on an EIGER X1 Md etector and at ransmission electron microscope. [9,[28][29][30][31] To date,e lectron crystallography only plays am inor role in structural chemistry.A so fS eptember 2018, the Inorganic Crystal Structure Database contained 425 single-crystal structures from electron crystallography compared with over 78 500 structures from X-ray crystallography.…”