An Efficient Reactive Force Field without Explicit Coordination Dependence for Studying Caustic Aluminum Chemistry

M Pouvreau and Q Guo and HW Wang and GK Schenter and CI Pearce and AE Clark and KM Rosso, JOURNAL OF PHYSICAL CHEMISTRY LETTERS, 14, 6743-6748 (2023).

DOI: 10.1021/acs.jpclett.3c01176

Reactive force fields (RFFs) are an expedient approachto samplechemical reaction paths in complex systems, relative to density functionaltheory. However, there is continued need to improve efficiencies,specifically in systems that have slow transverse degrees of freedom,as in highly viscous and superconcentrated solutions. Here, we presentan RFF that is differentiated from current models (e.g., ReaxFF) byomitting explicit dependence on the atom coordination and employinga small parameter set based on Lennard-Jones, Gaussian, and Stillinger-Weberpotentials. The model was parametrized from AIMD simulation data andis used to model aluminate reactivity in sodium hydroxide solutionswith extensive validation against experimental radial distributionfunctions, computed free energy profiles for oligomerization, andformation energies. The model enables simulation of early stage Al(OH)(3) nucleation which has significant relevance to industrialprocessing of aluminum and has a computational costthat is reduced by 1 order of magnitude relativeto ReaxFF.

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