Atomic Simulations of Hetero Coalescence of Cu₁₄₇ and Ag₁₄₇ Clusters

The hetero coalescences of the Cu₁₄₇ and Ag₁₄₇ clusters at room temperature and 1300 K have been simulated by molecular dynamics approaches within embedded atom method framework, and then the structural transformation of alloying clusters formed after the coalescence is investigated during heating and cooling. The activation energy is used to describe the potential barriers that need to be overcome to carry out the merger, the potential energy characterizes the structural transition the free energy difference reflects the driving force for the coalescence of the clusters. The simulation results show that different contacting modes and different distances between the two clusters at 300 K affect the heterogeneously coalescing processes and the alloying clusters formed, and that the increase in temperature greatly affects the motion of the atoms as well as the atomic packing structures within the alloying clusters. At the beginning of coalescence, the two clusters are in contact with each other, forming a connecting neck, and the Ag atoms diffuse along the surface of the Cu clusters. With the increase of temperature, Ag atoms gradually wrap around the Cu clusters, and the Cu clusters also undergo structural changes at high temperatures, and the Cu-Ag alloy clusters with different initial cohesive distances and cohesive orientations show different packing patterns. For the Cu-Ag clusters obtained via high-temperature coalescence, the cooling stage not only exhibits distinctly different structural transformation processes, but the structural transformation temperatures corresponding to each process also show significant differences.