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

Natalia E Koval,Ricardo Díez Muiño,Daniel Sánchez-Portal,Andrey G Borisov

doi:10.1186/1556-276x-7-447

Natalia E Koval, Ricardo Díez Muiño + Show 2 more

Open Access

https://doi.org/10.1186/1556-276x-7-447

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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.

Highlights

Photoemission spectroscopy is one of the most important techniques used to study the structure of molecules, surfaces, and solids [1]
We focus our attention on the combined dynamic screening of a static localized core hole and the photoemitted electron
We find an important influence of the hole screening dynamics on the force experienced by the emitted electron and, on the energy loss during the photoemission process

Summary

Introduction

Photoemission spectroscopy is one of the most important techniques used to study the structure of molecules, surfaces, and solids [1]. It is based on the photoelectric effect which was discovered more than 100 years ago by H. Attosecond techniques permit access to the time scale of electron motion in atoms, molecules, and solids. Due to this experimental advance, there is a growing interest in the theoretical description of the dynamic electronic processes taking place in the subfemtosecond time scale [3,4,5,6]

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