Structure solution with automated electron diffraction tomography data: different instrumental approaches

Over the past few years automated electron diffraction tomography has become an established technique for structure solution of nano-crystalline material. The intentional choice of an arbitrary tilt axis and thus, the use of nonoriented diffraction patterns (off-zone acquisition) together with fine equidistant sampling of the reciprocal space result in high quality intensity data sets. Coupling automated electron diffraction tomography with electron beam precession (Vincent & Midgley, 1994) enables sampling of intensities between the static slices of reciprocal space and therefore enhances the quality of intensity data further; relatively complex structures have been solved using 3D electron diffraction intensities extracted from automated electron diffraction tomography data. Automated electron diffraction tomography data was collected initially using a dedicated automated module. In this manuscript we demonstrate that electron diffraction data of comparable quality can be collected using manual technique that mimics the automated process. A rather difficult material, i.e. a low symmetric (triclinic) sodium tetratungstate (Na2W4O13) including heavy and light scatterers, was selected for testing. In this paper we show, that all collected data sets automatic and manual, with and without electron beam precession were able to provide data slightly different but suitable for ab initio structure solution and refinement.