ReaxFF (for “reactive force field”) is a bond order based force field developed by Adri van Duin, William A. Goddard, III, and co- workers at the California Institute of Technology for use, e.g., in molecular dynamics simulations. Whereas traditional force fields are unable to model chemical reactions because of the requirement of breaking and forming bonds (a force field's functional form depends on having all bonds defined explicitly), ReaxFF eschews explicit bonds in favor of bond orders, which allows for continuous bond formation/breaking. ReaxFF aims to be as general as possible and has been parameterized and tested for hydrocarbon reactions, alkoxysilane gelation, transition-metal-catalyzed nanotube formation, and high-energy materials.
Recently, ReaxFF has been developed to study oxygen interactions with realistic silica surfaces. This version of ReaxFF is based on highly accurate and benchmarking density functional studies. Highly accurate density functional results are achieved by employing Minnesota Functionals.