Energetic and Steric Effects in Ion/Surface Reactive Scattering

摘要

The principal investigator explored chemical reactions between small molecularions and solid surfaces in order to simulate reactions on spacecraft surfaces in a low-earth-orbit environment. The surfaces were prepared in ultrahigh vacuum, and the ions were accelerated to translational energies between 5 and 100 eV before they collided with the surface target. The scattered reaction products were detected with energy-, mass-, and angular resolution. Results are reported for dissociative scattering of OCS(+) on Ag(111), where three different mechanisms were assigned for the three observed fragmentation pathways. Experiments were also conducted on NO(+) reacting with O/Ag(111) and O/Al(111). Here, an atom abstraction channel led to the scattering of NO2. Finally, prolonged bombardment of a silicon nitride surface by low energy O(+) ions was observed to induce irreversible damage in the nitride thin film.