# Two-center electron-impact ionization via collisional excitation-autoionization

## TL;DR

This paper investigates how a neighboring atom can significantly enhance electron-impact ionization through a two-center excitation-autoionization process, revealing resonance effects and angular distribution influences.

## Contribution

It introduces a detailed theoretical analysis of two-center excitation-autoionization, highlighting resonance peaks and cross section enhancements in electron-impact ionization.

## Key findings

- Resonance peaks significantly increase ionization cross sections.
- Neighboring atoms influence angular distribution of ejected electrons.
- Two-center processes can dominate ionization under certain conditions.

## Abstract

Electron-impact ionization of an atom or ion in the presence of a neighboring atom is studied. The latter is first collisionally excited by the incident electron, whose energy is assumed to be high but nonrelativistic. Afterwards, the excitation energy is transferred radiationlessly via a two-center Auger process to the other atom or ion, leading to its ionization. We show that the participation of the neighboring atom manifests in a very pronounced resonance peak in the energy-differential cross section and can substantially enhance the total cross section of electron-impact ionization. We also discuss the influence of the neighbouring atom on the angular distribution of the ejected electron.