The effect of hydrocarbon chemistry on sputtering in mixed Be-C-H materials

Molecular dynamics simulations of low energy sputtering from mixed Be-C surfaces have been performed to gain an insight into the evolution and response of plasma facing components in current and projected fusion devices. An analytical bond-order potential (ABOP) for the ternary Be-C-H system was used to model the interactions. It was found that the presence of carbon required a more advanced description including chemical effects between carbon and hydrogen. To facilitate this, a method was constructed which combines the Brenner hydrocarbon potential [1] and the Be-C-H ABOP. To our knowledge this constitutes the first implementation of a method capable of simultaneously describing chemical hydrocarbon interactions and metallic bonding in molecular dynamics simulations. This model, which gives a more realistic description of low energy ion-surface interactions in the presence of carbon impurities, can also be extended to other fusion relevant mixed systems such as W-C-H.