Experiments with Clusters: Unraveling solvation effects upon electron attachment

Since more than two decades, there has been a significant interest in processes induced by low energy electrons in biologically relevant systems, especially in relation to DNA damage [1,2]. Ionizing radiation releases a large number of secondary electrons in cells. This secondary species with initial kinetic energies of up to few tens of eV may inelastically interact with building blocks of cells before they enter a (pre-)hydrated stage. It was shown that low energy electrons with energies < 15 eV can induce DNA damage in a film of plasmid DNA upon electron irradiation [1,2]. One of the underlying mechanisms of DNA damage on the molecular level was identified as dissociative electron attachment. Subsequently, a large number of experimental studies was carried out with isolated biomolecules in the gas phase [3]. In these mass spectrometric studies resonance energies as well as charged fragmentation products were determined.

However, studies with isolated molecules in the gas phase have the limitation that solvation effects are neglected. To bridge the gap between single molecules and the condensed phase, electron attachment studies with small biomolecular clusters have been carried out. In this contribution, I will first present an introduction about the basics of electron attachment to clusters, followed by an overview of the experimental approach to generate clusters. Then I will discuss few highlights of electron attachment studies with clusters of recent years, like for example with nitroimidazolic compounds [4], which remarkably showed how the electron attachment process is altered with solvation. 

 

[1]           E. Alizadeh, L. Sanche, Chem. Rev. 2012, 112, 5578–5602.

[2]           Y. Dong et al., J. Phys. Chem. B 2020, 124, 3315−3325

[3]           J.D. Gorfinkiel and S. Ptasińska, J. Phys. B: At. Mol. Opt. Phys. 2017, 50, 182001

[4]           R. Meißner et al., Nat. Commun. 10, 2388 (2019)