Grazing incidence fast atom diffraction for He atoms impinging on a Ag(110) surface

TL;DR

This study uses grazing incidence fast atom diffraction of helium on Ag(110) to test scattering models and potential calculations, achieving good agreement between theory and experiment.

Contribution

It introduces a combined approach using the surface eikonal approximation and DFT-derived potentials to model helium atom diffraction on Ag(110).

Findings

Good match between theoretical and experimental momentum distributions.

The surface eikonal approximation effectively captures quantum interference effects.

DFT-based potentials accurately describe projectile-surface interactions.

Abstract

Experimental diffraction patterns produced by grazing scattering of fast helium atoms from a Ag(110) surface are used as a sensitive tool to test both the scattering and the potential models. To describe the elastic collision process we employ the surface eikonal (SE) approximation, which is a semi-classical method that includes the quantum interference between contributions coming from different projectile paths. The projectile-surface potential is derived from an accurate density-functional theory (DFT) calculation that takes into account the three degrees of freedom of the incident projectile. A fairly good agreement between theoretical and experimental momentum distributions is found for incidence along different low-indexed crystallographic directions.