Scattering Theory

Abstract

The theoretical investigation and description of scattering (collision) processes of atomic particles represents an important field of application of Quantum Mechanics. One can gain therewith valuable information about particle interactions (e.g., nuclear forces), about elementary interaction potentials, about the structure of matter (e.g., crystal structures), and so on. The energetic structure of atoms and molecules, however, is spectroscopically investigated, where by any kind of energy supply the particle is transferred from its ground state into an excited state. The energy, which is emitted with the return into the ground state, e.g. in form of a photon, is analyzed. Initial and final state of the process stem from the discrete spectrum of the Hamilton operator (bound states). In contrast, it is typical for scattering processes that the initial and final state of the considered system both lie in the continuous part of the eigen-value spectrum. The scattered particle comes from infinity into the sphere of action of the scatterer, in order to be detected after the collision again asymptotically at infinity. The particle is therefore not in a bound state.