摘要
A highly charged ion (HCI) has a large potential energy, which is equal to the binding energies of all the elec-trons removed to create the ion. When such a slow HCI approaches and then enters into a solid surface, an \abovethe surface" and a \below the surface" hollow atom will be formed, respectively, by capturing electrons from thesurface into its empty levels. Not only new aspects of atom physics has been introduced by hollow atoms, but alsoHCI applications in material science has promising prospects, such as surface analysis, the synthesis of materialswith new properties, and the formation of nanostructure that have been an active area of research in recent years[1??6].
