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A: Atomphysik
A 18: Atom–/Ion–Oberflächen Wechselwirkungen
A 18.6: Talk
Thursday, April 6, 2000, 15:45–16:00, HS IV
Charge Transfer during Scattering of Slow Singly and Multiply Charged Ions at a LiF-Surface — •Ludger Wirtz1, Christoph Lemell1, Carlos O. Reinhold2, Lotten Hägg3, and Joachim Burgdörfer1 — 1Institut für Theoretische Physik, TU Wien, Austria — 2Oak Ridge National Laboratory, USA — 3Dep. of Physics and Mathematics, Mid Sweden University, Sundsvall, Sweden
The interaction of ions with surfaces can induce surface damage and modification. An important precursor event for these processes is the creation of holes in the valence band of the surface due to transfer of one or more electrons to the ion. We present Hartree-Fock calculations for the shift of the projectile energy levels due to the image and crystal potentials and for the deformation of the LiF band structure caused by the strong perturbing potential of the projectile. Furthermore, we calculate interaction potentials used in a simulation of the projectile trajectory and the lattice dynamics of the surface. Resonant electron transfer can occur when the capture level of the approaching ion is shifted below the valence band edge before the trajectory reaches the classical turning point. We compare our calculations with a recent measurement of the threshold for potential sputtering by singly charged ions [1].
[1] Hayderer et al, Phys. Rev. Lett. 83, 3948 (1999)