Monte-Carlo simulation of atom kinetics in intermetallics: Correcting the jump rates in Ni 3Al

Abstract

An improved Kinetic Monte-Carlo (KMC) algorithm for the simulation of atom configuration kinetics in intermetallics is introduced. In KMC a set of jump probabilities is computed from energy barriers. In transition state theory the barrier height is the difference between the initial equilibrium state and a saddle point state. It is on the latter that traditional treatments have made the most far-reaching assumptions, mostly setting it constant. A more detailed treatment of the saddle point state based on ab initio calculations of the actual jump profiles is proposed and demonstrated in Ni 3Al. It is shown in preliminary KMC simulations that individually computed saddle point energies make a considerable difference in jump statistics and overall kinetics of the long range order parameter.