Computer simulation of the sputtering of clusters

The article of record as published may be found at http://dx.doi.org/10.1063/1.323014The formation of clusters of sputtered copper atoms from an argon-bombarded (100) copper surface has been simulated with a computer program which includes interatomic attractive forces. Dimer formation is very common. Most commonly, dimers are formed from atoms which were next-nearest neighbors in the crystal. Nearest-neighbor atom clustering is rare, and dimer formation by a single atom moving in a channel has not been observed, and could not be forced by artificial means. All multimer formation mechanisms depend strongly upon both the relatively low speed of the sputtered atoms and the relatively high speed of the knock-on atoms involved in the sputtering mechanisms. Strong evidence for trimer formation exists. Pairs of dimers with a common atom have been observed. No quadrimers have been identified, but structures which almost meet the stability criteria have been observed. (AIP