Conclusion

In this paper we have reported the \(S_\text{e}\) of protons in copper in a very wide range of velocities. TDDFT-based electron dynamics is capable of capturing most of the physics in the different ranges, starting from non-linear screening effects, electron-hole excitations and production of plasmons. We disentangled channeling and off-channeling effects and observe a collapse of the two curves at low velocities; and identified four regimes i) the linear \(\mathrm{s}\)-only (\(0.02-0.07~\mathrm{a.u.}\)), ii) linear \(\mathrm{s}+\mathrm{d}\) (\(0.3-1~\mathrm{a.u.}\)), iii) crossover with \(\sim 1.5\)-power law (\(0.07-0.3~\mathrm{a.u.}\)) and iv) plasma-like (\(v > 1~\mathrm{a.u.}\)). This further illustrates that the electronic stopping in general does not possess a simple behavior in the limit \(v\to 0\), and that band and bound effects dominate this behavior.