ABSTRACT
The generalized form is known as the semiclassical theory of scattering and is based on classical trajectories. The wave function will be a complicated function of the coordinates of all the particles and, going from one scattering angle to another, it will change almost randomly. Atom and molecule potentials are strongly repulsive at short internuclear distances, so much so that below certain distances they can be considered to have a hard core. The difficulties in the problem appear when nuclear degrees of freedom are involved and are primarily caused by the fact that the solutions oscillate rapidly and that there are many channels. The fact that there are two waves means that the parts of the initial wave were scattered by the side wall at two impact angles and therefore were reflected into two different final states.
