a) Charge state distribution Outline

Collisions between highly charged ions (HCI) and solid surfaces are currently in the center of numerous experiments and theoretical investigations. The main motivation of these efforts is the study of the fundamental interaction mechanism between the HCI and the solid surfaces. The accurate knowledge of these processes is very important for the use of HCI as a surface diagnostic tool and as well as for surface modifications. Very recently, interactions of HCI with internal surfaces in microcapillaries have been introduced as an alternative technique to study above surface processes. Ions traveling approximately parallel to the capillary axis will be attracted by image forces toward the cylindrically shaped internal wall of the capillary (Fig.1.). Fig.1. Sketch of the ideal microcapillary with typical ion trajectories. ρc is the critical capture radius and dc is the critical capture distance While the dominant fraction of projectiles will either exit without undergoing charge transfers (trajectory type 1) or undergo close collisions with the surface similar to conventional grazing surface collisions (trajectory type 2), trajectories of type 3 will undergo only large-distance ``above surface' ' collisions near the exit surface of the wall