Abstract
Intensities of higher order reflections in a large angle convergent beam electron diffraction (LACBED) pattern are measured for α-Al2O3 and are compared with theoretical calculations in order to examine applicability of the kinematical approximation to determination of the structure factors. Effects of specimen thickness, temperature and absorption on the intensities are investigated through the dynamical theory of electron diffraction. A static displacement of Al3+ ions from their ideal positions in a unit cell of α-Al2O3 is determined from a relative change between two neighbouring high index reflections. The displacement determined through the kinematical theory of electron diffraction agrees well with the one through the dynamical theory and the ones measured by X-ray or neutron diffraction. The result demonstrates the usefulness of LACBED and the kinematical approximation.
