Slow electrons from clusters in strong Xray pulses

TL;DR

This paper investigates electron emission from clusters under intense X-ray pulses, revealing that both evaporation and direct photoemission contribute to the observed energy spectra, with an analytical model provided for the direct electrons.

Contribution

It demonstrates that direct photoelectrons significantly influence the near-threshold spectral features, challenging the assumption that low-energy electrons are solely from evaporation.

Findings

Both evaporation and direct photoemission shape the electron spectra.

A new analytical approximation for the direct photo-electron spectrum is introduced.

Low-energy electrons originate from multiple emission mechanisms.

Abstract

Electrons released from clusters through strong Xray pulses show broad kinetic-energy spectra, extending from the atomic excess energy down to the threshold, where usually a strong peak appears. These low-energy electrons are normally attributed to evaporation from the nano-plasma formed in the highly-charged clusters. Here, it is shown that also directly emitted photo electrons generate a pronounced spectral feature close to threshold. Furthermore, we give an analytical approximation for the direct photo-electron spectrum.