Model for multiple-collision trajectories in nonreactive atom--diatom collisions

The extent of the complex (multiple-collision) region (CR) is investigated for a classical nonreactive collinear atom--diatom system. A simple model to estimate the extent of the CR is given, based on the different roles the repulsive and attractive parts of the interaction potential V have in the collision. The model is extended to obtain more detailed information on the CR, such as the extent of m-collision regions within the CR. In the extended model, a multiple-collision trajectory is treated as a sequence of single-collision trajectories on a purely repulsive interaction potential V/subr/. The vibrational excitation produced by V and V/subr/ is compared, and it is pointed out that if the motion of the system with V is to be described adequately by V/subr/, it is necessary that multiple-collision trajectories do not occur