Test of the interatomic potential in the eV-region by glancing-angle scattering of He-atoms from Fe(0 0 1)

We report on experimental observation of multimodal angular distributions of 15 keV He0-atoms scattered under glancing angles from an Fe(0 0 1) surface along a [0 0 0] surface direction. Based on classical molecular dynamics computer simulations of atom trajectories we deduce the He±Fe interaction potential in the eV-energy range. Our experiments visualize the transition from axial to planar surface channeling. For our dynamical row-model to describe the experimental data well, we construct a mixed potential from two well-known potentials in the literature, the ``universalʹʹ potential for large distances and the ``individualʹʹ potential for close particle separation. In addition, the shift of the experimental angle spectra with respect to the calculated shows elastic horizontal bend of the real atomistic rows due to the scattering and about 10 times smaller vertical displacement. # 2001 Elsevier Science B.V. All rights reserved.