Resonant charge transfer during ion scattering on metallic surfaces

Electron transfer during low-energy ion scattering (LEIS) is discussed in the article. In most cases, the final charge state of ions/atoms scattered from a metallic surface is formed due to resonant charge transfer (RCT). The key concepts, model representations, and basic laws of electronic exchange are systemized in the article. For practical usage, RCT is primarily important for surface diagnostics by LEIS, because incorrectly taking into account electronic exchange can lead to significant errors. It is noteworthy, that LEIS has the best surface sensitivity and is indispensable for diagnosing the composition of the upper surface layer.