Origin of ~12 eV features in Li+ and Li2+ electron–ion coincidence spectra

Identify the physical mechanism responsible for the small maxima observed at electron kinetic energies around 12.0 eV (Li+) and 12.3 eV (Li2+) in electron spectra measured in coincidence with lithium ions for large helium nanodroplets irradiated at hν = 46.2 eV.

Background

When measuring electron spectra in coincidence with Li+ and Li2+ ions at hν ≈ 46 eV, the authors observe several prominent ICD features associated with He* and He2* decay channels. In addition to the expected peaks, there are smaller maxima near ~12 eV whose physical origin is not assigned.

Determining the mechanism behind these features is important for a complete understanding of secondary ionization pathways and ICD channels in lithium-doped helium nanodroplets under photoelectron-impact excitation conditions.