Band structure effects in high energy ion beam surface interaction at grazing incidence

Abstract

The analysis of charge state distributions after the interaction of fast Li-and N-ions with a surface at grazing incidence at energies between 50 and 350keV yields for Li a strongly suppressed and for N an enhanced fraction of neutrals in comparison to the beam-foil interaction. These findings are supported by corresponding alkali-spectra which are dominated by lines from transitions in singly ionized atoms. The experiments are consistently interpreted in terms of a two step model: (1) collisional excitation in the close vicinity of the surface and (2) modification of this population by resonant electron transfer from (to) non localized states in the conduction (valence) band to (from) the ion. The model is also applied to interpret recent beam-foil experiments where preferential populations of Rydberg levels in highly ionized atoms were found.

Complete density matrix of HeI 3p excited in fast grazing ion-surface collisions via “Hanle-effect”

“…After the early approach in terms of the "electron density gradient model" by Schr6der and Kupfer [5], resonant one-electron tunneling between surface and fast moving projectile has been shown to play an important role with respect to population and polarization of atomic terms in grazing surface scattering [6][7][8]. After the early approach in terms of the "electron density gradient model" by Schr6der and Kupfer [5], resonant one-electron tunneling between surface and fast moving projectile has been shown to play an important role with respect to population and polarization of atomic terms in grazing surface scattering [6][7][8].…”

Auger neutralization and ionization processes for charge exchange between slow noble gas atoms and solid surfaces

“…Although the influence of the crystal structure on the ion fractions of slow ions scattered from metals have been known for a long time [129,130,131,132,133], rather simple and general models [76,77,134] cannot explain the details of the experimental results. Therefore, a more realistic description of the metal surface is needed to account for observed crystal effects in the Auger rate.…”

Alignment of high rydberg states in hydrogen

“…'«s«a, However, some observations at lower n, and for other beam-foil excited systems, tm indicate different population dependences on n, which are sometimes not monotonic . jg (3,4). Observations of the polarization of the emission indicate asymmetries in the shape of the excited state wavefunction.…”