Enhanced ionization of embedded clusters by Electron Transfer Mediated Decay in helium nanodroplets

TL;DR

This paper reports the observation of electron transfer mediated decay (ETMD) in Mg clusters within helium nanodroplets, revealing a dominant ionization pathway and the formation of stable doubly-ionized species.

Contribution

It demonstrates for the first time that ETMD is the main ionization mechanism for embedded clusters in helium nanodroplets at certain photon energies.

Findings

ETMD is the dominant ionization process above helium's ionization potential.

Observation of stable doubly-ionized Mg clusters larger than 5 atoms.

Identification of a low energy ETMD peak in the photoelectron spectrum.

Abstract

Here, we report the observation of electron transfer mediated decay (ETMD) involving Mg clusters embedded in helium nanodroplets which is initiated by the ionization of helium followed by removal of two electrons from the Mg clusters of which one is transferred to the He environment neutralizing it while the other electron is emitted into the continuum. The process is shown to be the dominant ionization mechanism for embedded clusters for photon energies above the ionization potential of He. The photoelectron spectrum reveals a low energy ETMD peak. For Mg clusters larger than 5 atoms we observe stable doubly-ionized clusters. We argue that ETMD provides a new pathway to the formation of doubly-ionized cold species.