Multi-electron transitions induced by neutron impact on helium

TL;DR

This paper investigates how neutron impact can be used to study electron-electron correlations in helium, revealing unique ionization spectra and resonance behaviors distinct from other impact methods.

Contribution

It introduces a novel approach using neutron impact for excitation and ionization studies, providing detailed ab-initio spectra and highlighting differences from traditional photoionization.

Findings

Doubly excited resonances are prominent in neutron impact spectra.

The double to single ionization ratio differs from photon and charged particle impacts.

Neutron impact reveals unique many-body effects in helium ionization.

Abstract

We explore excitation and ionization by neutron impact as a novel tool for the investigation of electron-electron correlations in helium. We present single and double ionization spectra calculated in accurate numerical ab-initio simulations for incoming neutrons with kinetic energies of up to 150 keV. The resulting electron spectra are found to be fundamentally different from photoioniza- tion or charged particle impact due to the intrinsic many-body character of the interaction. In particular, doubly excited resonances that are strongly suppressed in electron or photon impact become prominent. The ratio of double to single ionization is found to differ significantly from those of photon and charged particle impact.