Influence of the polarization in grazing scattering of fast hellium atoms from LiF(001) surfaces

TL;DR

This paper introduces a distorted-wave eikonal method to analyze how polarization influences grazing scattering of fast helium atoms from LiF(001) surfaces, successfully matching experimental angular distributions.

Contribution

The study develops a new eikonal approach incorporating polarization effects to better understand grazing scattering phenomena.

Findings

Polarization significantly affects scattering along <110> direction.

The eikonal model accurately reproduces experimental angular distributions.

Polarization effects are negligible along <100> direction.

Abstract

Grazing scattering of neutral atoms from insulator surfaces is investigated in the intermediate velocity range, in which interference effects have been recently observed. To describe this process we introduce a distorted-wave method, based on the use of the eikonal wave function, which takes into account the phase of the scattering state along the classical projectile path. 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 polarization produced 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. The proposed eikonal approach, including polarization effects, provides angular projectile spectra in good agreement with the experimental data.