Channeling regimes in ion surface scattering

We report on surface channeling experiments of singly charged ions on single crystal surfaces of Pt(1 1 0) and Pd(1 1 0). Using a time-of-flight system installed in forward direction we analyze the energy distribution of the scattered projectiles. By variation of the primary energy and the angle of incidence we investigate effects of the perpendicular energy on the channeling features. The perpendicular energy is defined as E⊥ = E0sin2ψ with ψ the angle of incidence. In combination with precise azimuthal rotations of the crystal, we are sensitive to axial channeling and obtain information about the limits of axial surface channeling. From a comparison with detailed trajectory calculations we find that axial channeling effects are most pronounced for a perpendicular energy between 5 and 20 eV. As a result, we obtain an exemplary channeling map for the interaction of nitrogen ions with the (1 × 2) reconstructed Pt(1 1 0) surface identifying different channeling regimes.