Molecular dynamics simulation of hydrogen atom sputtering on the surface of graphite with defect and edge

We report effects of graphite vacancy and hydrogen isotopes in chemical sputtering due to hydrogen atoms onto graphite surfaces by use of molecular dynamics simulation. A modified Brenner reactive empirical bond order potential, which was benchmarked using ab initio CCSD(T) and hybrid DFT potential energy curves, was used to compute energies and gradients during the MD simulations. Interlayer intermolecular interaction between layers of graphite was represented by original potential model. By the injection of hydrogen atoms, a graphite of perfect crystal was peeled off one by one from a surface clearly, while a graphite including vacancies was amorphized simultaneously. The graphite including monovacancies was amorphized more strongly than graphite including divacancies. Flux of carbon atoms detached from the surface by hydrogen atom bombardment increases linearly as incident energy increases. The effects of isotope is that the time at which the hydrogen atom bombardment start producing hydrocarbon molecules increases as the mass of a hydrogen isotope increases.