Bold advances in force fields: The ReaxFF reactive force field

COMP 79

Adri CT. van Duin, duin@wag.caltech.edu and William A. Goddard III, wag@wag.caltech.edu. Materials and Process Simulation Center, California Institute of Technology, Beckman Institute (139-74), Pasadena, CA 91125
Empirical force field methods (FF) methods are magnitudes faster the quantum mechanics (QM) based methods, allowing applications to large atomistic systems and enabling molecular dynamics calculations on the nanosecond timescale at a relatively modest computational expense. These advantages have helped FF methods find wide-spread application. However, FF-methods have suffered from three major disadvantages: 1) Non-reliability. 2) Non-transferability. 3) Non-reactive. Over the last six years we have developed ReaxFF, which addresses these disadvantages and provides a reliable, transferable method for the atomistic-scale study of chemical reactions. Using bond-order/bond distance principles we obtained a FF-method capable of properly describe chemical bond dissociation. This, combined with a polarizablecharge distribution, made ReaxFF applicable to a wide range of materials and interfaces between different materials. ReaxFF parameters are based on QM rather than on sparsely available experimental data, which greatly improves its reliability and allows ReaxFF to properly describe reactants, products and transition states.