Cluster ion, Sputtering
We studied the fragmentation of sputtered clusters due to Cu-cluster impact on a Cu surface using MD simulations. The sputtered clusters become stable after the successive fragmentation of nascent sputtered clusters. Then the vibration energy spectrum of sputtered clusters is independent on the incident cluster size and energy. For sputtered clusters Cun (n>4), it has a peak, whose energy corresponds to the melting temperature of Cu. The recombination is not important. Most of the monomers come from direct ejection; the clusters are produced mainly by fragmentation.
