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Reactive force field optimization and MnFeO3 catalyst theoretical investigation

In a recent unpublished research of catalytic activity of several MnMOx (M = Cu, Fe, Ni) metal-oxide catalysts the Reactive force field (ReaxFF) method has been shown to model well such processes. The investigation raised interest in developing parameters for calculation of mixed metal-oxide species, which were at the time non-existent. Here we present first and preliminary results of training the ReaxFF for the Mn-Fe-O-C interaction. The training set of 39 structures consisting of at minimum the Mn, Fe and O atoms, obtained in their crystal form from Materials Project database [1, 2]. Each step in parameter optimization has been done performing MD minimization of 5000 steps of 0.1 fs using the NVT/Berendsen thermostat. Parameters were optimized using the parabolic search as implemented in the original van Duin code [3] with some in-home modifications. First, optimization is performed at temperature of 1 K. Initial parameters are then re-optimized using the same training set at temperatures 300 K and 500 K. The force field is applied to the process of toluene adsorption/degradation on MnFeO3 catalyst. Results obtained show agreement to previous experimental expectations, although some remarks are given, since the presumed crystal structure of Mn1-xFexO3 may have major impact for such theoretical predictions.

ReaxFF, MD simulation, parameter optimization, MnFeO3

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