Repulsive potentials for low energy projectiles incident on copper surfaces

Interatomic potentials that are relevant for low energy (<2 keV) projectiles (X = He, Cl, Ar, Cu) incident on the Cu(1 0 0) and Cu(1 1 1) surfaces (represented by Cu10 clusters), and on isolated Cu atoms, have been calculated from first principles using density functional theory. For energies above 10-20 eV, the diatomic X-Cu potentials provide acceptable approximations (typically within 1-2 eV) to the corresponding potentials for the surface environment.