Resonant charge transfer in low-energy ion scattering: Information depth in the reionization regime

• Published in: Surface science Vol. 605; no. 21-22; pp. 1913 - 1917
• Main Authors: Primetzhofer, D., Spitz, M., Taglauer, E., Bauer, P.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 01.11.2011; Elsevier; North-Holland Pub. Co
• Subjects: Backscattering; Charge exchange; Charge transfer; Collisions; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Ion fraction; Ion scattering; Low-energy ion scattering; Mathematical models; Neutralization; Origins; Physics; Reionization; Single crystal; Spectra; Ion fraction; Charge exchange; Low-energy ion scattering; Reionization; Single crystal; Neutralization; Ion scattering analysis; Monocrystals; Charge transfer
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/j.susc.2011.07.006

Time-Of-Flight Low-energy ion scattering (TOF-LEIS) experiments were performed for He+ ions scattered from Cu(100) and Cu0.5Au0.5(100). Probabilities for resonant neutralization and reionization in close collisions were deduced in a wide energy range. To learn about the information depth in LEIS, in a next step ion spectra were analyzed for polycrystalline Cu samples. The relative yield of backscattered projectiles, which have undergone distinct charge exchange processes, was calculated. Results indicate a strong contribution to the ion yield that origins from particles reionized in a close collision in deeper layers when experiments are performed at energies where reionization is prominent. The surface sensitivity of the ion signal at different energies is quantified. Based on these results, the total ion spectrum was quantitatively modelled by two consistent, but different approaches. ► Charge exchange probabilities for low energy noble gas ions studied experimentall. ► Modeling of the energy spectra of backscattered ions made possible. ► Information depth in LEIS can be understood now in the reionization regime. ► Depth distribution of charge exchange events is determined.