Sputtering of hydrocarbons by ion-induced breaking of chemical bonds

While the physical sputtering of atoms caused by keV and MeV ions has been studied extensively both by molecular dynamics (MD) simulation and experime nts, the mechanisms leading to atom and molecule erosion at energies simila r to1-100 eV are not very well understood. We now describe how low-energy h ydrogen ions can cause erosion of carbon atoms and hydrocarbon molecules by entering the region of a carbon-carbon chemical bond and hence breaking it , a process we call 'swift chemical sputtering'. In the particular case of hydrogen bombardment of carbon-based materials, we further show that this c an lead to erosion yields far exceeding those expected for a physical sputt ering process. (C) 2001 Elsevier Science B.V. All rights reserved.