The role of excitation states in particle-surface interactions

The interactions of atoms and molecules at surfaces depend on their precise excitation state (electronic, vibrational, rotational). For incident atoms, the “perceived” surface potential can differ substantially with the electronic state. In the case of molecules, vibrational excitation enhances dissociation and subsequent reaction probabilities. Due to orientation effects, rotational excitation can have a significant influence on the level of reactivity in the molecule-surface interaction. Results are presented regarding the interaction of plasma-produced particles with bare and pre-covered metal surfaces. Plasma excitation produces a range of excited species. A particular focus is placed on interactions involving reactive N atoms. Novel features are observed in the scattering and reactions of these atoms, which are attributed to marked differences in the interactions of different excited states. Possibilities with regard to targeted enhancement of molecular chemistry are