A computer program for the evaluation of orientation relationships from simple electron-diffraction spot patterns

A computer program is described, which allows the determination of the orientation relationship between crystals on a specimen from electron-diffraction spot patterns with arbitrary and, therefore, simple zone axes in both crystals. From the respective positions of the two goniometer axes the orientational relationship is obtained via a specimen coordinate system defined by the foil normal and the second goniometer axis, which is fixed with respect to the specimen. Depending on the crystal symmetry several rotation matrices are obtained, which describe the rotation necessary to make the unit cells or, in the case of crystals belonging to different crystal systems, the respective normalized orthogonal coordinate systems of the two crystals coincide.