Influence of the prefactor to defect motion in α-Iron during long time scale simulations

We present a study of the influence of the prefactor in the Arrhenius equation for the long time scale motion of defects in α-Fe. It is shown that calculated prefactors vary widely between different defect types and it is thus important to determine these accurately when implementing on-the-fly kinetic Monte Carlo (otf-KMC) simulations. The results were verified by reproducing many events using Molecular Dynamics (MD) and Temperature-Accelerated Dynamics (TAD). The calculated prefactor was shown to increase the relative interstitial-vacancy diffusion rates by an order of magnitude compared to the assumption of a constant prefactor value and the ordering of the rate table for the interstitial defect migration mechanisms was also changed. In addition, low prefactor values were observed for the 4 interstitial dumbbells configuration with low barrier transitions.