The Reax Force Field, ReaxFF, is a bond order-based computational approach used in molecular dynamics simulations to model the potential energy space of atomic models. In general, standard molecular mechanics force fields are insufficient to describe chemical reactions, because of their inability to simulate bond formation and breaking. However, in ReaxFF, the energy contributions from bonded interactions, such as bonds, angles, torsions, etc., are calculated as functions of the bond order, which is dynamically calculated based on the interatomic distance. ReaxFF parameters also include non-bonded interactions, such as van der Waals forces and Coulombic (electrostatic) interactions. A detailed discussion on the transferability and training of ReaxFF parameters can be found elsewhere . As is the case with empirical force fields, ReaxFF is trained to reproduce physical and chemical space as either observed in experiments or calculated by reliable quantum mechanics (QM) -based methods. The force field training objective is to minimize the error function defined in Eq. 1,