Benchmark of ReaxFF Force Field for Subcritical and Supercritical Water

Water in the subcritical and supercritical states has remarkable properties that make it an excellent solvent for oxidation of hazardous chemicals, waste separation, and green synthesis. Molecular simulations are a valuable complement to experiments in order to understand and improve the relevant sub- and super-critical reaction mechanisms. Since water molecules under those conditions can act not only as solvent but also as reactant, dissociative force fields are specially interesting to investigate theseprocesses. In this work, we evaluate the capacity of the ReaxFF force field to reproduce the microstructure, hydrogen bonding, dielectric constant, diffusion, and proton transfer of sub- and super-critical water. Our results indicate that ReaxFF is able to simulate water properties in these states in very good quantitative agreement with existing experimental data, with the exception of the static dielectric constant which is reproduced only qualitatively.