Study of low energy noble gas ion reflection from monocrystalline surfaces; Influence of thermal vibrations of the surface atoms: IV. Possibilities for the estimation of the actual ion-atom interaction potential

The angular and energy distributions of low energetic noble gas ions, reflected over 30° from a copper (100) target, are measured and compared with calculations. In the simulations the chain-model approach was applied. The interaction potential is estimated by fitting the calculated results to the experiments. This procedure is achieved by varying the screening length of the used Thomas—Fermi potential in the approximation of Molière. Information about the actual interaction potential can be obtained in three complementary ways: (1) from the width of the angular distributions of ions, reflected (quasi) singly along a low index direction, (2) from the height ratio of the QD and the QS peak and (3) from the width of the QS peak. The resulting values for the fitted screening lenghts appear to be notably smaller than the theoretical ones. A comparison of the experimental and calculational widths of the distributions as a function of the temperature seems to suggest the presence of correlations between thermal displacements of neighbouring surface atoms.