Van der Waals contribution to the inelastic atom-surface scattering

TL;DR

This paper calculates the inelastic scattering rate of Xe atoms on Cu(111) focusing on Van der Waals interactions, comparing different substrate response models and highlighting the significant role of surface states.

Contribution

It introduces a detailed calculation of inelastic atom-surface scattering considering Van der Waals forces and compares two substrate response models, emphasizing the surface state's impact.

Findings

Surface state contributes about 50% to electron-hole pair excitation.

The Random Phase Approximation provides a detailed substrate response.

Van der Waals interactions are significant in low and intermediate velocity regimes.

Abstract

A calculation of the inelastic scattering rate of Xe atoms on Cu(111) is presented. We focus in the regimes of low and intermediate velocities, where the energy loss is mainly associated to the excitation electron-hole pairs in the substrate. We consider trajectories parallel to the surface and restrict ourselves to the Van der Waals contribution. The decay rate is calculated within a self-energy formulation. The effect of the response function of the substrate is studied by comparing the results obtained with two different approaches: the Specular Reflection Model and the Random Phase Approximation. In the latter, the surface is described by a finite slab and the wave functions are obtained from a one-dimensional model potential that describes the main features of the surface electronic structure while correctly retains the image-like asymptotic behaviour. We have also studied the influence of the surface state on the calculation, finding that it represents around 50% of the total probability of electron-hole pairs excitation.