Molecular-dynamics study of cluster growth by cluster-cluster collisions

The formation of silicon clusters from cluster-cluster collisions at 2400 K is followed in time using molecular dynamics. It is found that during the first picosecond after collision, the clusters tend to agglomerate forming an intermediate complex in which the individuality of the original clusters is kept. However, during the following few picoseconds, atoms in the newly united cluster are highly mobile and agglomeration is lost. New clusters are hotter and with time they evaporate single atoms. This irreversible process by which the cluster accommodates the collision energy was studied as a function of the energy and the impact parameter. On average, the sticking coefficient is 1.