Time-dependent density-functional theory is used to calculate the energy loss of antiprotons and protons traversing metal clusters of variable size. We find that the effective energy loss per unit path length inside the cluster shows no significant cluster size effects over the wide range of projectile velocities studied. This allows us to compare the calculated stopping power with the experimental values for a solid metal target. Excellent agreement between the theoretical results and recent experimental data is found for velocities below the inner-shell excitation threshold. We thus present a nonperturbative quantum-mechanical approach to obtain the energy loss of charges in solids. © 2007 The American Physical Society.

Financial support by the Basque Departamento de Educación, Universidades e Investigación, the University of the Basque Country UPV/EHU (Grant No. 9/UPV 00206.215- 13639/2001), the Spanish MEC (Grant No. FIS2004-06490- C03-00), and the EU Network of Excellence NANOQUANTA (Grant No. NMP4-CT-2004-500198) is acknowledged. The work of I.N. was partially supported by the Hungarian OTKA (Grant Nos. T046868 and T049571).

Peer Reviewed