The atomistic simulation of catalytic materials on timescales relevant to catalytic processes remains a significant computational challenge. One route to overcome this challenge is to map the dynamics onto discrete states on the potential energy surface and hop between them using transition-state theory (TST) and Kinetic Monte Carlo (KMC). Here, we describe our recent efforts to couple adaptive KMC with reactive force fields required for catalysis applications. Particularly, we study the kinetics of core-shell inversion in PdAu bimetallic nanoparticles.  We find that the dynamics proceeds by an initial period of fast exchange between surface and subsurface atoms. However, subsequently the dynamics is dominated by low-barrier surface rearrangement. This leads to combinatorially large superbasins, which challenges standard KMC methods. Our efforts to improve aKMC algorithms to handle very large superbasins will be discussed.<br/>

Extending attainable timescales in molecular dynamics simulations using adaptive Kinetic Monte Carlo: structural rearrangements in catalytic core-shell nanoparticles

2019 Spring National Meeting

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