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 yi
eld of proton sputtering from hydrogen-containing C-60 strongly increa
ses 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 ve
ry weakly on the incident energy and the incident charge, which is con
sistent with the prediction of the classical-over-the barrier model.