Investigation of the formation of iron nanoparticles from the gas phase by molecular dynamics simulation

Abstract

The formation of iron particles from the supersaturated gas phase is investigated by molecular dynamics simulation. The atomic interaction is modelled with a recent parameterization of the embedded atom method which is able to describe the bcc phase of bulk iron. The influence of the state conditions such as temperature and density on the growth mechanisms of the iron particles is analysed. With the common neighbour analysis method the structural changes of the particles over the course of the growth process is traced. Furthermore, the surface fraction is investigated as an order parameter for the morphology of the particles. It appears that in the early state of the growth process the atomic structure is dominated by icosahedral structures which are, over the course of the growth process, transformed into other structures such as fcc or hcp. Iron atoms in the bcc structure were not found for small particles. The structural reorganization depends mainly on the temperature of the system and on the magnitude of the heat removal from the system. The results are in agreement with experimental and other theoretical investigations on the structure of iron nanoparticles.