Second order classical perturbation theory for atom surface scattering: analysis of asymmetry in the angular distribution

TL;DR

This paper develops a second order classical perturbation theory for atom-surface scattering that explains observed asymmetries in angular distributions, especially for soft potentials, and provides analytic and numerical results for specific models.

Contribution

It introduces a second order classical perturbation approach that captures asymmetries in atom-surface scattering, extending previous first order theories.

Findings

The theory explains asymmetry reduction with increased incident energy.

Analytic expressions are derived for exponential and Morse potentials.

Numerical implementation matches experimental asymmetry features.

Abstract

A second order classical perturbation theory is developed and applied to elastic atom corrugated surface scattering. The resulting theory accounts for experimentally observed asymmetry in the final angular distributions. These include qualitative features, such as reduction of the asymmetry with increased incidence energy as well as asymmetry in the location of the rainbow peaks with respect to the specular scattering angle. The theory is especially applicable to "soft" corrugated potentials. Analytic expressions for the angular distribution are derived for the exponential repulsive and Morse potential models. The theory is implemented numerically to a simplified model of the scattering of an Ar atom from a LiF(100) surface.