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

Abstract

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.

Simulating the superheating of nanomaterials due to latent heat release in surface reconstruction

“…We find ν d = 50.1, 1.5, and 0.16 ps −1 for Type I, II and III transitions, respectively. These numbers are comparable to the values found by other workers [61,62].…”

Oriented Attachment Revisited: Does a Chemical Reaction Occur?

“…With the calculated energy barriers, we can estimate the rate constant for the diffusion process by assuming that the frequency factor A to be $10 12 s À1 . 33,34 The values of K are 8.3 3 10 À9 s À1 , 2.7 3 10 À9 s À1 , 6.9 3 10 À7 s À1 , and 3.1 3 10 À105 s À1 , for the diffusion of CO 3…”

Adsorption and Diffusion of H Atoms on β-PtO2 Surface: The Role of Nuclear Quantum Effects

“…For the diffusion path IIE  C, P Q is slightly larger than P C , while the order is inverse (P Q < P C ) for IIA  IID, due to the larger barrier width in path IIA  IID than in IIE  C (Table II, 3.76 Å vs 1.87 Å). Based on the probability of surmounting the barriers (Table II), the reaction constant can be estimated by multiplying an attempting frequency of the adsorbed atom, which is the order of 10 12 s -1 [59,60].…”