(9f) Pushing the Frontiers of Accessible Scales in Kinetic Monte Carlo Simulations of Heterogeneous Catalysts

Kinetic Monte Carlo (KMC) simulations are instrumental in the multi-scale modelling of surfaces and interfaces. As an example, such simulations are frequently used to elucidate the complex reaction dynamics exhibited by solid catalysts and predict macroscopic performance metrics, such as activity and selectivity. However, the length- and time-scales accessible by sequential KMC implementations are limited, and handling lattices with millions of sites has been prohibitive due to large memory requirements and long simulation times. Domain decomposition approaches could address these limitations, but they require sophisticated algorithms for conflict resolution at the boundaries between subdomains. Jefferson’s Time-Warp algorithm addresses this challenge via rollbacks and re-simulations which correct any and all causality violations arising transiently during simulation. Thus, the exact dynamics of the chemical master equation are finally reproduced.

We have recently coupled the Time-Warp algorithm with the Graph-Theoretical KMC framework enabling the handling of complex adsorbate lateral interactions and reaction events within very large lattices. This approach has been implemented in Zacros, our general-purpose KMC software, and has been validated and benchmarked for efficiency in model systems as well as realistic chemistries. This work makes Zacros the first-of-its-kind general-purpose KMC code with distributed parallelisation capability to study heterogeneous catalysts.