Potential sputtering of protons from a surface under slow highly charged ion bombardment

Sputtering phenomena have been experimentally studied for slow highly charged ions ( 0.5-4.8 keV Ar q + ( q =4-16)). It is found that (1) the yield of proton sputtering from hydrogen-containing C 60 strongly increases with the charge state of the incident ion, (2) the energy spectra of sputtered protons consist of two components which are identified as potential sputtering and conventional kinetic sputtering, and (3) the peak energy and width of the potential sputtering component depend very weakly on the incident energy and the incident charge, which is consistent with the prediction of the classical-over-the barrier model.