Development of a Charge-Implicit ReaxFF Potential for Hydrocarbon Systems

Molecular dynamics (MD) simulations continue to make important contributions to understanding chemical and physical processes. Concomitant with the growth of MD simulations is the need to have interaction potentials that both represent the chemistry of the system and are computationally efficient. We propose a modification to the ReaxFF potential for carbon and hydrogen that eliminates the time-consuming charge equilibration, eliminates the acknowledged flaws of the electronegativity equalization method, includes an expanded training set for condensed phases, has a repulsive wall for simulations of energetic particle bombardment, and is compatible with the LAMMPS code. This charge-implicit ReaxFF potential is five times faster than the conventional ReaxFF potential for a simulation of keV particle bombardment with a sample size of over 800 000 atoms.