Molecular shape effect in polyatomic ion–surface scattering. Surface-induced dissociation of Fe(C5H5)2+ and FeC5H5+ at Si(100)

Fe(C5H5)2+ and FeC5H5+ ions undergo ligand dissociation upon collision with an Si(100) surface at hyperthermal energy (5–120 eV). The dissociation starts at a collision energy of 5 eV for the both ions, in agreement with the reaction energetics. However, the dissociation yield for FeC5H5+ is much lower than for Fe(C5H5)2+ at the energies above the dissociation threshold. This result suggests that the molecular shape has a strong influence on the short-time dynamics of polyatomic ion dissociation at a surface.