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Beyond mean-field approximations for accurate and computationally efficient models of on-lattice chemical kinetics

Pineda, M; Stamatakis, M; (2017) Beyond mean-field approximations for accurate and computationally efficient models of on-lattice chemical kinetics. Journal of Chemical Physics , 147 (2) , Article 024105. 10.1063/1.4991690. Green open access

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Abstract

Modeling the kinetics of surface catalyzed reactions is essential for the design of reactors and chemical processes. The majority of microkinetic models employ mean-field approximations, which lead to an approximate description of catalytic kinetics by assuming spatially uncorrelated adsorbates. On the other hand, kinetic Monte Carlo (KMC) methods provide a discrete-space continuous-time stochastic formulation that enables an accurate treatment of spatial correlations in the adlayer, but at a significant computation cost. In this work, we use the so-called cluster mean-field approach to develop higher order approximations that systematically increase the accuracy of kinetic models by treating spatial correlations at a progressively higher level of detail. We further demonstrate our approach on a reduced model for NO oxidation incorporating first nearest-neighbor lateral interactions and construct a sequence of approximations of increasingly higher accuracy, which we compare with KMC and mean-field. The latter is found to perform rather poorly, overestimating the turnover frequency by several orders of magnitude for this system. On the other hand, our approximations, while more computationally intense than the traditional mean-field treatment, still achieve tremendous computational savings compared to KMC simulations, thereby opening the way for employing them in multiscale modeling frameworks.

Type: Article
Title: Beyond mean-field approximations for accurate and computationally efficient models of on-lattice chemical kinetics
Open access status: An open access version is available from UCL Discovery
DOI: 10.1063/1.4991690
Publisher version: http://doi.org/10.1063/1.4991690
Language: English
Additional information: © 2017 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). [http://dx.doi.org/10.1063/1.4991690]
Keywords: Science & Technology, Physical Sciences, Chemistry, Physical, Physics, Atomic, Molecular & Chemical, Chemistry, Physics, MONTE-CARLO-SIMULATION, MASTER EQUATION, CO OXIDATION, PT(111), ADSORPTION, OXYGEN, GAS, NO, THERMODYNAMICS, COMPLEXITY
UCL classification: UCL
UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Chemical Engineering
URI: https://discovery.ucl.ac.uk/id/eprint/1560160
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