Modelling swift heavy ion irradiation in iron

Swift heavy ions moving in metals lose most of their energy to inelastic scattering of electrons. The energy deposited in the electronic system is transferred into the atomic system via electron–ion interactions and can lead to melting and creation of new damage and also annealing of pre-existing atomic defects. Using a combination of molecular dynamics and a consistent treatment of electron energy transfer and transport we have modelled experiments performed in Fe to investigate the annealing effect and damage creation under electronic excitations. We observe both annealing and new damage creation at low and high electronic stopping, respectively. Rapid separation of interstitial atoms and vacant lattice sites is seen due to efficient transport via replacement collision sequences. Our results suggest that the role of electronic excitation can be significant in modeling of the behaviour of metals under swift heavy ion irradiation and attempts to modify metals via ion implantation.