currently I'm studying for my master's examination in physical chemistry. The topic will be surfaces and catalysis. To prepare myself I'm reading "Surface Science - An introduction" by Oura. Unfortunately some chapters are less precise than others and therefore I'm wondering if someone could explain the image formation in low energy electron microscopy to me. In the book it is written that a diffraction pattern will form, since the electrons are scattered by the surface. Then one of the diffracted beams is selected by the aperture to form the whole image.
At this point I'm quite confused. How is it possible to just use one of the diffracted beams to built up the whole surface image? As far as i know (at least from x-ray crystallography) the diffraction pattern can be considered as the fourier transform of the lattice. Therefore selecting just one diffracted beam should lead to a massive loss of information.
Thank you very much in advance!