A new endstation for extreme-ultraviolet spectroscopy of free clusters and nanodroplets

TL;DR

This paper introduces a new experimental endstation at a synchrotron facility designed for advanced EUV spectroscopy of free clusters and nanodroplets, enabling detailed studies of their photophysical and photochemical properties.

Contribution

The paper presents a novel endstation combining a cluster and nanodroplet source with advanced coincidence imaging spectroscopy for the first time.

Findings

Successful demonstration of photoelectron-photoion coincidence experiments

High-resolution yield spectra and ion mass spectra obtained

Versatile platform for studying energy transfer in nanosystems

Abstract

We present a new endstation for the AMOLine of the ASTRID2 synchrotron at Aarhus University, which combines a cluster and nanodroplet beam source with a velocity map imaging and time-of-flight spectrometer for coincidence imaging spectroscopy. Extreme-ultraviolet spectroscopy of free nanoparticles is a powerful tool for studying the photophysics and photochemistry of resonantly excited or ionized nanometer-sized condensed-phase systems. Here we demonstrate this capability by performing photoelectron-photoion coincidence (PEPICO) experiments with pure and doped superfluid helium nanodroplets. Different doping options and beam sources provide a versatile platform to generate various van der Waals clusters as well as He nanodroplets. We present a detailed characterization of the new setup and present examples of its use for measuring high-resolution yield spectra of charged particles, time-of-flight ion mass spectra, anion-cation coincidence spectra, multi-coincidence electron spectra and angular distributions. A particular focus of the research with this new endstation is on intermolecular charge and energy-transfer processes in heterogeneous nanosystems induced by valence-shell excitation and ionization.