The measurement of intensities in the Rotation Electron Diffraction Technique

•Intensity data are recorded as a set of frames during stepwise rotation about an arbitrary axis.•A precise description of the diffraction geometry throughout the rotation movement has been given.•The defined rotation axis was the basic element to extract the intensity data and to calculate the excitation error.•To develop the RED method, a precise description of the diffraction geometry throughout the rotation movement has been given.•Reflections, which do not reach the maximum intensity, will not be included in the structure solution and refinement strategy. The Rotation Electron Diffraction Technique, recently developed at the University of Stockholm, has been used to acquire three-dimensional electron diffraction data. A mathematical expression to calculate the excitation errors, sg, is suggested by considering the diffraction geometry and the rotation axis. In order to plot the rocking curves, diffraction patterns taken from CoP3 cubic structure (a=7.708Å, space group Im3¯) are used as examples. Intensities of some reflections are derived by Multigauge software during the beam tilt series. Rocking curves for two Friedel pair reflections with different angles from the rotation axis are plotted.