title: Effect of nonlinearity in hybrid kinetic Monte Carlo-continuum models.
abstract: Recently there has been interest in developing efficient ways to model heterogeneous surface reactions with hybrid computational models that couple a kinetic Monte Carlo (KMC) model for a surface to a finite-difference model for bulk diffusion in a continuous domain. We consider two representative problems that validate a hybrid method and show that this method captures the combined effects of nonlinearity and stochasticity. We first validate a simple deposition-dissolution model with a linear rate showing that the KMC-continuum hybrid agrees with both a fully deterministic model and its analytical solution. We then study a deposition-dissolution model including competitive adsorption, which leads to a nonlinear rate, and show that in this case the KMC-continuum hybrid and fully deterministic simulations do not agree. However, we are able to identify the difference as a natural result of the stochasticity coming from the KMC surface process. Because KMC captures inherent fluctuations, we consider it to be more realistic than a purely deterministic model. Therefore, we consider the KMC-continuum hybrid to be more representative of a real system.
authors.affiliation: Pacific Northwest National Laboratory P.O. Box 999, Richland, WA 99352, USA. ariel.balter@pnl.gov
authors.forename: Ariel
authors.initials: A
authors.lastname: Balter
authors.forename: Guang
authors.initials: G
authors.lastname: Lin
authors.forename: Alexandre M
authors.initials: AM
authors.lastname: Tartakovsky