Empirical potential for hydrocarbons for use in simulating the chemical vapor deposition of diamond films

TLDR

The authors develop an empirical many‑body potential for hydrocarbons that models intramolecular bonding in small molecules, graphite, and diamond lattices. The potential is built on Tersoff's covalent‑bonding formalism, augmented with corrections for radical overbinding and nonlocal effects. The potential reproduces experimental atomization energies, correctly predicts surface reconstructions and hydrogen adsorption energetics, and, due to its short range and fast evaluation, is suitable for large‑scale molecular‑dynamics simulations of reacting hydrocarbons.

Abstract

An empirical many-body potential-energy expression is developed for hydrocarbons that can model intramolecular chemical bonding in a variety of small hydrocarbon molecules as well as graphite and diamond lattices. The potential function is based on Tersoff's covalent-bonding formalism with additional terms that correct for an inherent overbinding of radicals and that include nonlocal effects. Atomization energies for a wide range of hydrocarbon molecules predicted by the potential compare well to experimental values. The potential correctly predicts that the \ensuremath{\pi}-bonded chain reconstruction is the most stable reconstruction on the diamond {111} surface, and that hydrogen adsorption on a bulk-terminated surface is more stable than the reconstruction. Predicted energetics for the dimer reconstructed diamond {100} surface as well as hydrogen abstraction and chemisorption of small molecules on the diamond {111} surface are also given. The potential function is short ranged and quickly evaluated so it should be very useful for large-scale molecular-dynamics simulations of reacting hydrocarbon molecules.