ABSTRACT
This chapter examines the most critical properties, which make the collision phenomenon substantially different from the corresponding problem of bound states in quantum mechanics. In order to elaborate the treatments further in the course of the presented analysis, it was necessary to employ the quantum-mechanical entities, such as the equations of time evolution, as well as the state vectors and the Hilbert space of eigenstates. A given picture of quantum mechanics can be more practical than formalism for the examined physical phenomenon. Hence, the choice of the optimal picture of quantum mechanics becomes a matter of considerable practical importance. The initial state Ψ0i is experimentally prepared, i.e. characterized by means of the impulse, polarization, spin, isospin and other internal quantum numbers of the constituent parts of the scattering system.
