Modeling the Freezing of Molten Copper Nanoclusters: The Effect of Quenching Temperature and Cluster Size

Molecular dynamics simulations have been conducted to study structural changes of Cu clusters during quenching processes. It is shown that quenching temperature greatly affects atom motions and structural formation of these clusters. Simulation results establish the following pathway of the structural changes by using mean square displacements (MSDs), a pair analysis (PA) technique, pair distribution functions (PDFs) as well as atom packing. With decreasing the quenching temperature, more atoms are bound into the cages formed by their neighbor atoms. Accompanying with continuous interchange positions among atoms, local structures of the clusters are changed. The scenario of cluster structures at these quenching temperatures is greatly different on increasing the cluster size. Atom diffusive behavior is helpful to form the stable icosahedral structures. Too low quenching temperature limits growth of small local structures.