Charge and excitation state of Na projectiles scattered from Al surfaces

This work addresses the issue of the anomalous neutralization of slow sodium ions at aluminum surfaces by measuring spectra of Auger electrons emitted by collisionally excited sodium projectiles. The anomalous fraction of scattered singly charged ions is due to the Auger decay of singly excited projectiles. Electron emission experiments reveal a sizeable production of doubly charged ions that should be observed in ion fraction measurements. Measurements at varying incidence angles provide a rather detailed description of the successive stages of the inelastic scattering events that determine the charge state of scattered projectiles.