Dynamic screening of a localized hole during photoemission from a metal cluster

TL;DR

This paper investigates how the dynamic screening of a localized hole in a metal cluster influences the energy and trajectory of a photoemitted electron, revealing velocity-dependent effects crucial for understanding electron losses in metals.

Contribution

It introduces a semi-classical model combining TDDFT and classical electron motion to study real-time screening effects during photoemission from metal clusters.

Findings

Dynamic screening reduces energy loss of photoelectrons.

Screening effects are velocity-dependent.

Initial electron-hole interactions significantly impact electron trajectories.

Abstract

Recent advances in attosecond spectroscopy techniques have fueled the interest in the theoretical description of electronic processes taking place in the subfemtosecond time scale. Here we study the coupled dynamic screening of a localized hole and a photoelectron emitted from a metal cluster using a semi-classical model. Electron density dynamics in the cluster is calculated with Time-Dependent Density Functional Theory and the motion of the photoemitted electron is described classically. We show that the dynamic screening of the hole by the cluster electrons affects the motion of the photoemitted electron. At the very beginning of its trajectory, the photoemitted electron interacts with the cluster electrons that pile up to screen the hole. Within our model, this gives rise to a significant reduction of the energy lost by the photoelectron. Thus, this is a velocity dependent effect that should be accounted for when calculating the average losses suffered by photoemitted electrons in metals.