Theory of atomic scattering

This qualitative account serves to underline the complexity of the physical processes involved in forming the ion image, and the difficulty of arriving at a detailed interpretation. Neither the theory of atom scattering at surfaces, nor the description of field ionization are sufficiently advanced to allow a quantitative account of image intensities. However, such a quantitative evaluation is not really necessary in... 

Positrons and Positronium in Gases, P A. Fraser Classical Theory of Atomic Scattering,... 

In these lectures we will present the theory of atomic scattering focusing in particular on the atom surface potential. This potential is separated in an attractive part of the Van der Waals type and in a repulsive part related to the surface charge which is approximate as a superposition of atomic charges. The lateral Fourier trasform of this potential, which enters in the cross sections, has a gaussian form which is essential in order to explain the falling off of the Rayleigh peaks at the zone boundary. 

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