ELECTRONIC STOPPING OF HYDROGEN-IONS IN GRAPHITE AND AMORPHOUS-CARBON

The physical and chemical state of a medium is of importance for ion stopping, especially at low ion velocities (v less-than-or-equal-to v(F)) where the valence electrons dominate the stopping process. In this contribution the stopping cross section of graphite and of evaporated carbon were measured by Rutherford backscattering for hydrogen ions in the range 25 to 150 keV/u. A larger stopping cross section for amorphous carbon than for graphite, up to 5%, has been found. These results are interpreted in terms of the nonlinear density-functional theory, which describes electronic stopping in an electron gas self-consistently, the only target parameter being the electron gas density.