A versatile setup for studying size and charge-state selected polyanionic nanoparticles

TL;DR

This paper presents a flexible experimental setup for generating and studying size and charge-state selected polyanionic nanoparticles, demonstrated with metal clusters and capable of producing highly negative charge states.

Contribution

The authors introduce a modular, rf-based setup that allows sequential electron attachment after mass-selection, enabling the study of heavy, highly charged polyanionic nanoparticles.

Findings

Successfully produced Ag₈₀₀^{7-} clusters.

Analyzed electronic and optical properties via photoelectron spectra.

Demonstrated flexibility for various anionic species.

Abstract

Using the example of metal clusters, an experimental setup and procedure is presented, which allows for the generation of size and charge-state selected polyanions from monoanions in a molecular beam. As a characteristic feature of this modular setup, the further charging process via sequential electron attachment within a 3-state digital trap takes place after mass-selection. In contrast to other approaches, the rf based concept permits to access heavy particles. The procedure is highly flexible with respect to the preparation process and potentially suitable for a wide variety of anionic species. By adjusting the storage conditions, i.e., the radio frequency, to the change in the mass-to-charge ratio, we succeeded to produce clusters in highly negative charge states, i.e., Ag$_{800}^{7-}$. The capabilities of the setup are demonstrated by experiments extracting electronic and optical properties of polyanionic metal clusters by analyzing the corresponding photoelectron spectra.