We develop a model for heavy ion collisions that takes place in two stages, the first in which the ions interact through a Coulomb potential and the second in which they form a compound particle. A time-dependent boundary condition between the two stages is proposed at the point of coincidence of the two ions. When applied to stationary states this condition gives the standard single resonance R matrix and the corresponding S matrix shows the usual relation between the actual width of the level and its value when there is no Coulomb interaction. This dynamical model allows us to follow in time the process of scattering of ions for a single resonance, and it can be generalized to more complex situations.

• Received 3 August 1990

DOI:https://doi.org/10.1103/PhysRevC.43.311