Comparison of experimental and simulated low energy alkali ion scattering

Computer simulations performed using the MARLOWE code are compared with experimental results obtained for 1 keV Li⁺ ion scattering from W(001). Trajectory analysis using distributions of impact points, deflections and maximum penetration depths allow characterization of the contributing scattering mechanisms. Computer simulation is found to reproduce many of the observed features in the energy distributions and in the incident angle dependence, but there are also important differences. In agreement with experiment, a sharp, surface sensitive binary collision peak is found at certain angles but at others this peak may broaden, shift to lower energy and grow in intensity due to subsurface scattering mechanisms. Simulations overestimate the relative scattering intensity near critical edges and the importance of focused scattering from second layer atoms.