RESONANT EFFECTS IN THE STOPPING POWER OF CLUSTERS

The stopping power of large (H-2)(n)-clusters in silicon is analyzed a s a function of the cluster size and the cluster velocity. A dielectri c formalism is used to describe the electronic interaction between the projectile and the target. The intramolecular and intermolecular inte rference effects in the cluster energy loss are evaluated as a functio n of the cluster velocity. For high velocities and large clusters the intermolecular collective effects dominate in the cluster stopping pow er. For each cluster velocity we find a resonant cluster size for whic h the intermolecular stopping power clearly shows a maximum and it sat urates to a constant value for larger clusters. The radius of this res onant cluster and the maximum stopping power are proportional to the c luster velocity.