Channeling and hyper-channeling phenomena at metal surfaces

Abel Robin

Rijksuniversiteit Groningen, Atomic Physics - KVI, 
Zernikelaan 25, 9747 AA Groningen, The Netherlands


Since the decision of ITER being build in Europe the interaction of plasma 
with surfaces raises strong interest. Understanding the details of the 
interaction process of ions with surfaces is an essential task for constructing 
a rigid fusion power-plant. What can we learn from surface channeling in this 
respect? During the past decades, many experimental techniques have been 
elaborated using channeling to analyze the surface structure (LEIS, MEIS), thin 
layer compositions (RBS), and the surface potential and electronic corrugation. 
Next to information about the scattering material also information about atomic 
and molecular features of the projectile are obtained, e.g. the capture and 
decay rates in hollow atom formation, or how the surface potential influences 
molecular dissociation.
This talk gives a survey on the field of ion-surface channeling emphasizing 
the inelastic processes related with electronic surface corrugation. It turns 
out that ion surface channeling is very sensitive to the density corrugation 
at the surface making this technique a valuable tool to study electronic 
corrugation effects on the energy loss spectra and to use this information 
e.g. for identifying adsorbate sites.