any diffraction is pretty much always dependent (or I would rather say defined by) to the structural parameters of material. What kind of diffraction technique do you use? Is it LEED, RHEED or dark field in the TEM? In principle, ANY of diffraction pattern would be related to atomic positions in your specimen (more exactly, they would be related to the electron density distribution). The modulation of diffraction spots intensities upon changing electron energy is related to your specimen's surface symmetry and structural parameters of your specimen perpendicular to the surface (in the case of low-energy electron diffraction)... I suggest you look up more information on electron diffraction on wikipedia or elsewhere in the Internet. In order to answer your question in more detail, we need more details.