Calculation of the electron diffraction intensities using the multi-slice method

Abstract

For the calculation of the dynamical electron diffraction amplitude using the multi-slice method the slice thickness Δ z must be carefully selected. Crystals with long lattice periods parallel to the electron beam must be subdivided into m projected potential slices ( φ m ) of thickness Δ Z m . Image simulations for Nb 12 O 29 on the [100] orientation ( a = 28.9 Å) at 200 kV for various slice thicknesses gave the best fit to the experimental image for Δ z = 4.8 and 9.6 Å (6 and 3 slices pro unit cell), respectively. At higher accelerating voltage and better resolution, more beams contribute to the image; in this case Δ z must be decreased. In addition (independently of the calculation method), it is shown that errors in interpretation also occur, if the relativistic mass effect is neglected in the scattering equations.