Influence of the lighting on Fast Atom Diffraction studied via a semi-quantum approach

TL;DR

This paper investigates how the collimating conditions of incident beams influence fast atom diffraction patterns on crystal surfaces using a semi-quantum SIVR approach, highlighting the sensitivity to aperture parameters.

Contribution

It introduces a semi-quantum SIVR model that incorporates realistic collimating parameters to study diffraction patterns, providing new insights into the effects of collimator geometry.

Findings

Diffraction spectra are highly sensitive to collimating slit width.

Longer collimating apertures introduce additional interference structures.

The model aligns with experimental observations of azimuthal angle dependence.

Abstract

The influence of the collimating conditions of the incident beam on diffraction patterns produced by grazing scattering of fast atoms off crystal surfaces is studied within a semi-quantum approach, named Surface Initial Value Representation (SIVR) approximation. In this approach we incorporate a realistic description of the incident particle in terms of the collimating parameters, which determine the surface area that is coherently illuminated. The model is applied to He atoms colliding with a LiF(001) surface after passing through a rectangular aperture. As it was experimentally observed [1], SIVR spectra as a function of the azimuthal angle are very sensitive to the width of the collimating slit. We also found that the length of the collimating aperture affects polar angle distributions, introducing additional interference structures for the longer collimating slits.