MOLECULE AND CLUSTER BOMBARDMENT - ENERGY-LOSS, TRAJECTORIES, AND COLLISION CASCADES

The penetration of energetic molecules and clusters through solid mate rial and associated radiation effects may be looked at as the sum of e vents induced by independent atoms. This picture is often adequate as a first approximation but it has definite limitations. The present pap er reviews physical effects which cause more or less drastic modificat ions of this first-order picture. A number of sources of nonlinearitie s and correlations are identified. The emphasis is laid on stopping, m ultiple scattering, and collision-cascade kinematics. The discussion i s mostly qualitative and based more on intuitive arguments and a few e xperimental results than on quantitative models.