While quantum mechanical (QM) methods allow for highly accurate atomistic scale simulations, their high computational expense limits applications to fairly small systems (generally smaller than 100 atoms) and mostly to statical, rather than dynamical, approaches. Force field (FF) methods are magnitudes faster than QM-methods, and as such can be applied to perform nanosecond-dynamics simulations on large (>>1000 atoms) systems. However, these FF-methods can usually only describe a material close to its equilibrium state and as such can not properly simulate bond dissociation and formation.
This lecture will describe how the traditional, non-reactive FF-concept can be extended for application including reactive events by introducing bond order/bond distance concepts. Furthermore, it will address how these reactive force fields can be trained against QM-data, thus greatly enhancing their reliability and transferability. Finally, this lecture will describe recent applications of the ReaxFF reactive force fields to a wide range of different materials and applications. These will specifically include applications to combustion, catalysis and material failure.
Burton Morgan 121, Purdue University, West Lafayette, IN