SQERTSS: Dynamic rank based throttling of transition probabilities in kinetic Monte Carlo simulations

Danielson, Thomas; Sutton, Jonathan E.; Hin, Céline; Savara, Aditya

doi:10.1016/j.cpc.2017.05.016

Cited by 28 publications

(28 citation statements)

References 33 publications

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“…10, are examined, it is found that adsorption and diffusion events dominate; therefore, these adsorption and diffusion processes are limited (''throttled'') by a stiffness scaling method. [64][65][66][67][68] The other most common events are H 2 O and OH decomposition, which are also seen to be reversible in nature. The OH molecule reacts with the CO molecule to form carboxyl which subsequently generates CO 2 ; while the OH molecule may break down, thereby producing oxygen which then reacts with CO to form CO 2 via direct CO oxidation.…”

Section: Kinetic Monte Carlo Simulationmentioning

confidence: 99%

A DFT and KMC based study on the mechanism of the water gas shift reaction on the Pd(100) surface

Chutia

Thetford

Stamatakis

et al. 2020

Phys. Chem. Chem. Phys.

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Section: Kinetic Monte Carlo Simulationmentioning

confidence: 99%

A DFT and KMC based study on the mechanism of the water gas shift reaction on the Pd(100) surface

Chutia

Thetford

Stamatakis

et al. 2020

Phys. Chem. Chem. Phys.

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“…2 ). Prefactor rescaling is a common multiscale technique in KMC to advance the time clock to long times 32 – 35 without impacting the results (see Supplementary Note 7 ). After prefactor rescaling, small cluster ( n ≤ 3) diffusion is at least 100 times faster than other events (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The adsorption/desorption and diffusion events have very dissimilar rates that makes a KMC simulations sample only fast quasi-equilibrated events 32 . A suitable downscaling of the rate constants of quasi-equilibrated events does not change the simulation outcome 33 – 35 . Here, we auto-scale the pre-exponential factors of fast events in Zacros and analyze simulation results using the Wrapper 54 .…”

Section: Methodsmentioning

confidence: 99%

Real-time dynamics and structures of supported subnanometer catalysts via multiscale simulations

Wang

Kalscheur

et al. 2021

Nat Commun

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Understanding the performance of subnanometer catalysts and how catalyst treatment and exposure to spectroscopic probe molecules change the structure requires accurate structure determination under working conditions. Experiments lack simultaneous temporal and spatial resolution and could alter the structure, and similar challenges hinder first-principles calculations from answering these questions. Here, we introduce a multiscale modeling framework to follow the evolution of subnanometer clusters at experimentally relevant time scales. We demonstrate its feasibility on Pd adsorbed on CeO2(111) at various catalyst loadings, temperatures, and exposures to CO. We show that sintering occurs in seconds even at room temperature and is mainly driven by free energy reduction. It leads to a kinetically (far from equilibrium) frozen ensemble of quasi-two-dimensional structures that CO chemisorption and infrared experiments probe. CO adsorption makes structures flatter and smaller. High temperatures drive very rapid sintering toward larger, stable/metastable equilibrium structures, where CO induces secondary structure changes only.

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“…[ 18–22 ] The rate constant rescaling methods are the most popular, which commonly feature rescaling rate constants of fast processes at quasi‐equilibrium. [ 23–28 ] However, a more complex timescale disparity problem is raised in systems with multiple reaction pathways. A minimal catalytic system of this kind has a fast reaction pathway of A + * → A* → B* → * + B and a slow side reaction pathway of A + * → A* → C* → * + C (* denotes an unoccupied active site, X* denotes adsorbed species X on an active site).…”

Section: Introductionmentioning

confidence: 99%

The enhanced extended phenomenological kinetics method to deal with timescale disparity problem among different reaction pathways

et al. 2020

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Kinetic Monte Carlo method can provide valuable mechanistic insights for catalytic systems. Nonetheless, it suffers from the notorious problem of timescale disparity due to the existence of the complex catalytic network that consists of fast events and slow events. Previously, we have proposed the extended phenomenological kinetics (XPK) method that effectively deals with the timescale disparity problem between diffusion and reaction. However, it remains a great challenge to simulate systems with timescale disparity among different reaction pathways, which is important when selectivity is the major concern. In this study, we implement the enhanced XPK method to address this problem. The new algorithm works by identifying states connected through fast transitions and compressing them into a “superstate” when the chosen states satisfy a local steadystate condition. This state compression algorithm simplifies the reaction network by concealing the fast transitions. The accuracy and efficiency of the algorithm are demonstrated by two model systems: selective catalytic hydrogenation and selective catalytic decomposition. The enhanced XPK method is expected to be beneficial to the kinetic simulations of catalytic systems, especially those with complex reaction networks.

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SQERTSS: Dynamic rank based throttling of transition probabilities in kinetic Monte Carlo simulations

Cited by 28 publications

References 33 publications

A DFT and KMC based study on the mechanism of the water gas shift reaction on the Pd(100) surface

A DFT and KMC based study on the mechanism of the water gas shift reaction on the Pd(100) surface

Real-time dynamics and structures of supported subnanometer catalysts via multiscale simulations

The enhanced extended phenomenological kinetics method to deal with timescale disparity problem among different reaction pathways

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