Proton energy loss in allotropic forms of carbon

We have investigated theoretically the electronic stopping of protons in different solid forms of carbon: glassy, amorphous, graphite, diamond and C₆₀-fullerite. The energy loss is described within the dielectric formalism and the target properties are modelled by a sum of Mennin-type energy loss functions. For each allotropic carbon form, we observe remarkable differences in the stopping cross section and in the energy loss straggling at proton velocities around and lower than that corresponding to the maximum in the energy loss. A comparison of our results with available experimental data shows a reasonably good agreement.