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Energy and Charge Transfer for Na+ Ions Scattered from a Ag(001) Surface

We present energy- and charge-resolved measurements of low and hyperthermal energy Na+ ions scattered from a Ag(001) surface. With the primary ion beam oriented along the [110] crystal direction, distinct peaks in the energy distributions of the scattered beam flux that correspond to single or multiple collisions with target atoms are observed. A classical trajectory simulation reveals that these collisions can occur either at the surface or within the [110] channels, depending on incident beam energy. Within the simulation we probe the role of finite temperature and thermally displaced atoms on specific scattering events and show that contributions to the scattered distributions from single and double collisions dominate within the [110] channels. We also report velocity dependent measurements of the neutral/ion ratio of the scattered beam flux. A deviation between the data and simulated charge transfer results is observed for Na trajectories which penetrate the surface.