Polarization effects in elastic scattering of swift He atoms from LiF(001) surfaces

M.S. GRAVIELLE; J.E. MIRAGLIA

Francia

Workshop; 17th. International Workshop on Inelastic Ion-Surface Collisions (IISC); 2008

International Committee of the IISC

In this work we investigate grazing scattering of neutral atoms from insulator surfaces in the intermediate velocity range, in which interference effects have been recently observed [1-3]. To describe this process we introduce a distorted-wave method, named surface eikonal approximation, which is valid for small de Broglie wavelengths of incident atoms. This method makes use of the eikonal wave function to represent the elastic collision with the surface, while the projectile movement is classically described, taking into account different initial conditions. The eikonal theory is applied to evaluate the angular distribution of few keV helium atoms after impinging on a LiF(001) surface along low index crystallographic directions. The interest focuses on the role played by the projectile polarizationproduced by cations and anions of the crystal surface.For the considered collision system we found a polarization channel, corresponding to the direction <110>, which is affected by this effect, while for incidence in the direction <100> the polarization contribution is nearly negligible.