Competition between electron and phonon excitations in the scattering of nitrogen atoms and molecules off tungsten and silver surfaces

TL;DR

This paper develops a theoretical framework to analyze energy dissipation mechanisms during nitrogen atom and molecule scattering on tungsten and silver surfaces, highlighting phonon excitations as the dominant process.

Contribution

It introduces a full-dimensional dynamics model combining electron-hole pair and phonon excitations with ab-initio potentials for surface scattering.

Findings

Phonon excitation dominates energy loss in scattering.

Electron-hole pair excitation is a minor contribution.

Adiabatic approximation captures key scattering dynamics.

Abstract

We investigate the role played by electron-hole pair and phonon excitations in the interaction of reactive gas molecules and atoms with metal surfaces. We present a theoretical framework that allows us to evaluate within a full-dimensional dynamics the combined contribution of both excitation mechanisms while the gas particle-surface interaction is described by an ab-initio potential energy surface. The model is applied to study energy dissipation in the scattering of N$_2$ on W(110) and N on Ag(111). Our results show that phonon excitation is the dominant energy loss channel whereas electron-hole pair excitations represent a minor contribution. We substantiate that, even when the energy dissipated is quantitatively significant, important aspects of the scattering dynamics are well captured by the adiabatic approximation.