Molecular Dynamics Simulation of Nanocluster Formation in a Supersonic Nano Nozzle Fabricated by Anodizing the Aluminum

Abstract

A molecular dynamics method has been developed and applied for simulation of a supersonic Ne gas expansion through a convergingdiverging nozzle. Although the classical nucleation theory is able to explain some physics of the nucleation processes, however, due to the physical inaccuracy of the classical nucleation theory for small clusters, molecular dynamic method is more usable for studying gas flows having clusters. Pressure, flow velocity, temperature were parameters that extracted by MD method along the central x-axis. The nucleation and condensation of the clusters and their transient and equilibrium behavior are other parameters that are investigated in this simulation. The results show that although with suitable conditions the formation of clusters in a nanonozzle is possible, but the size of clusters is much smaller than its counterpart in macro scale and clusters with especial magic numbers are formed. The proposed novel method for fabrication this kind of nanonozzle is multi-step anodizing of the aluminum. This nanonozzle which can be fabricated experimentally can be used in Ionized Cluster Beam Deposition (ICBD) method.