Variable charge reactive potential for hydrocarbons to simulate organic-copper interactions.

A variable charge reactive empirical potential for carbon-based materials, hydrocarbons, organometallics, and their interfaces is developed within the framework of charge optimized many-body (COMB) potentials. The resulting potential contains improved expressions for the bond order and self-energy, which gives a flexible, robust, and integrated treatment of different bond types in multicomponent and multifunctional systems. It furthermore captures the dissociation and formation of the chemical bonds and appropriately and dynamically determines the associated charge transfer, thus providing a powerful method to simulate the complex chemistry of many-atom systems in changing environments. The resulting COMB potential is used in a classical molecular dynamics simulation of the room temperature, low energy deposition of ethyl radicals on the Cu (111) surface (a system with ∼5000 atoms) to demonstrate its capabilities at describing organic-metal interactions in a dynamically changing environment.