ELECTRON-CAPTURE AND ENERGY-LOSS IN SIMILAR-TO-100 KEV COLLISIONS OF ATOMIC AND MOLECULAR-IONS ON C-60

We have determined absolute attenuation and electron capture cross sec tions in similar to 100 keV collisions between atomic ions of moderate charge states (He+, He2+, Ar2+, Ar3+, Ar4+, Xe2+, Xe3+, Xe4+) and C-6 0 molecules in the gas phase. The measured cross-sections support prev ious findings of the charge dynamics within C-60 from electron capture experiments with higher ionic charges. For a non-negligible fraction of the capture events we observed substantial ionic energy loss (less than or equal to 2 keV), which is ascribed to collisions where the ion passes through the C-60 molecule. Furthermore, we found that a molecu lar ion (100 keV CO22+) that captures an electron from C-60 can lose s imilar amounts of energy without dissociating. It is concluded that th e predominant contribution to the ionic energy loss comes from electro n excitation and ionization. (Int J Mass Spectrom 177 (1998) 51-62). ( C) 1998 Elsevier Science B.V.