Coincident measurements of projectile energy loss and kinetic electron emission yield for grazing scattering of 150 eV/amu to some keV/amu neutral hydrogen and helium atoms from an atomically clean and flat Al(111) surface allow us to correlate electron emission and inelastic interaction mechanisms at a metal surface. Our data show evidence for a threshold behavior of kinetic electron emission which is interpreted by energy transfer in binary encounters of projectiles in the electron selvage of a quasi-free electron gas. Contributions of electron emission to projectile energy loss are found to be negligibly small.

• Received 18 December 2002

DOI:https://doi.org/10.1103/PhysRevB.67.121405