ReaxFF Force Field in Molecular Dynamic Simulation of Reactive Systems

In this review article, the potential functions of the reactive force field ReaxFF used in reactive molecular dynamics (RMD) simulations are introduced and described. This force field with its special potential functions is used to simulate chemical reaction systems with accuracies close to those of quantum chemical calculations within reasonable computation times, even with about one million atoms on high-performance computing facilities. Variations of the partial charges of atoms during chemical reactions can also be calculated and probed within RMD simulations with accuracies very close to those calculated by density functional methods. In addition to the general potential functions incorporated in non-reactive force fields, in ReaxFF force field, there are a number of special (usually complex) potential functions describing details of the bonding structures and charge states of atoms in different coordination states and chemical and solvent environments. All of these potential functions are described in this paper, and examples are calculated and plotted to demonstrate clearly their behavior and their corresponding chemical and physical backgrounds. Finally, important evolutions of the ReaxFF force field and a few of its applications have been presented.