| CPC G01N 23/20058 (2013.01) [G01N 23/2055 (2013.01); G01N 2223/0566 (2013.01)] | 15 Claims |
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1. A method for determining a crystal structure model for a crystal, wherein the crystal is capable of electron diffraction, comprising steps:
obtaining electron diffraction data from the crystal by three-dimensional electron diffraction, wherein the data comprises information on crystal diffraction patterns, wherein each diffraction pattern comprises information on scattered electron intensities in each direction and crystal orientation to an incident electron beam during data acquisition, wherein the crystal is rotating or tilting during recording of the diffraction data; and
processing the data determining crystal lattice parameters, crystal orientation at the time of diffraction pattern acquisition, indices of each reflection and the scattered electron intensity of each reflection on each diffraction pattern, thereby producing the processed data;
generating virtual diffraction frames by a computer program, wherein each virtual diffraction frame comprising a list of integrated scattered electron intensities for each direction with summed contributions from diffraction patterns forming one virtual frame, the virtual diffraction frames being formed by calculation from the obtained three-dimensional electron diffraction data;
providing an approximate crystal structure model; and
refining the approximate crystal structure model using dynamical diffraction theory, wherein the refining comprising steps:
calculating modeled intensities of scattered electrons using dynamical diffraction theory based on the approximate crystal structure model; and
minimizing the difference between experimentally determined scattered electron intensities and modeled intensities, wherein the refined crystal structure model is the model with the smallest deviation.
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