Diffraction of fast heavy noble gas atoms, Ar, Kr and Xe on a LiF(001) surface, changing the tip of a ‘perfect’ AFM

We investigate experimentally the diffraction of fast atoms of noble gas on a LiF(001) crystal oriented along the [100] and [110] directions. All exhibit some quantum features but wavelengths are so short that these effects are qualitatively described by semi-classical models. With increasing mass and energy, the scattering profiles show an increasing number of diffraction peaks forming an increasing number of supernumerary rainbow peaks but progressively weakening in contrast with the innermost peaks correspond to individual quasi-specular Bragg peaks disappearing first. Along the [100] direction, all observed azimuthal profiles are well described by Bessel functions allowing a simple semi-quantitative analysis. After removing the contributions of the attractive forces, we show how the surface corrugation amplitude and its variation strongly depend on the probing atom. These data should be compared with those accessible with an atomic force microscope (AFM).