THE MASS-DISTRIBUTION OF SPUTTERED METAL-CLUSTERS .2. MODEL CALCULATION

The mass distribution of clusters M(n) sputtered from an fcc metal sur face is studied by a combination of molecular dynamics and Monte Carlo simulation. The cluster emission mechanism is subdivided into i) the formation of ''nascent'' clusters during the lifetime of the collision cascade developing in the solid and ii) the unimolecular decompositio n of excited unstable nascent clusters yielding stable ''final'' fragm ents. It is shown that the size distribution of the cluster yields Y(n ) measured far away from the surface can be roughly described by a pow er law (Y is-proportional-to n(-delta)), the exponent delta being stro ngly dependent on the bombarding conditions.