A Reaxff Reactive Force-field for Proton Transfer Reactions in Bulk Water and its Applications to Heterogeneous Catalysis

Abstract

We have developed a ReaxFF reactive force-field description for bulk water and for proton transfer in the aqueous phase. This ReaxFF potential was parameterized exclusively against quantumchemical (QM) data, describing a broad range of intra- and intermolecular water interactions, including H–H, HO–OH and O=O bond dissociation energies, charge distributions, angle bending energies, binding energies for [H2O]2–35-clusters, H-transfer reactions pathways in H3O+/H2O, [H2O]n and HO−/H2O-clusters and ice densities and cohesive energies. We find good agreement between ReaxFF and QM for all these cases. We found that this QM-based ReaxFF potential gives a good description of bulk water phases and proton migration, reproducing experimental density, radial distribution and diffusion data, while it overestimates proton diffusion in the OH−/water system. We anticipate that this ReaxFF water description, in combination with ongoing ReaxFF-work on amines, carboxylic acids, phosphates and inorganic materials, should be highly suitable for simulating biochemical reactions involving enzymes and DNA. Furthermore, this potential can be used to simulate water reactions and proton diffusion on metal and metal oxide surfaces, opening up applications to catalysis, crystal growth and crack propagation studies. We have provided a specific example of this force field to heterogeneous catalysis, showing an oxygen/hydrogen recombination reaction in an iron nanoparticle.

On the water structure at hydrophobic interfaces and the roles of water on transition-metal catalyzed reactions: A short review

“…The fluctuations can be modulated based on the strength of interactions between water and the surface. [101,113,120] Reactive force fields such as ReaxFF [121] may play a very helpful role in understanding the specific roles of H 2 O on transition metal-catalyzed reactions. These force fields are parameterized using data from quantum mechanics and then used in "classical" molecular dynamics (or Monte Carlo).…”

A reactive molecular dynamics simulation of the silica-water interface

“…To extend ReaxFFSiO͑2003͒ to these reactions, we first replaced the O/H parameters with a set of ReaxFF O/H parameters fitted against water-clusters and proton-transfer reactions in H 3 O + ͓H 2 O͔n and OH − ͓H 2 O͔ n systems. 31 Keeping the O/H parameters fixed, we subsequently refitted the Si/O, Si/Si, and Si/H bond and angle parameters against the QM-based training set data used to fit ReaxFFSiO͑2003͒. These data included bond dissociation curves for all Si/O/H bond combinations, angle distortion energies for all Si/O/H angle combinations, and equations of state for bulk-Si and bulk-SiO 2 -data.…”

Water adsorption beyond monolayer coverage on ZnO surfaces and nanoclusters

“…The current force field model is based on the ZnO parameters from ref [22]. The force field was extended to include the interaction with water by including the water parameters from ref [23]. To ensure the quality of this extension, additional data points were added to the training set, and the ZnO parameters were reparameterized to improve the fit (resulting in a small change of the original parameters).…”