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FELion 22-pole ion trap

O. Asvany, S. Brünken, P. Jusko, S. Banhatti, A. Stoffels, S. Schlemmer – University of Cologne

The FELion cryogenic 22-pole ion trap instrument, designed and built in Cologne in collaboration with the FELIX team, has been installed at the FELIX beamline in October 2014. The instrument allows the gas-phase spectroscopic characterization of mass-selected, internally and kinetically cold (T > 4 K) molecular ions by different action spectroscopic methods, e.g. Laser Induced Reactions (LIR), Infrared Multiple Photon Dissociation (IRMPD), InfraRed Pre-Dissociation (IRPD), or IR/UV double resonance dissociation.

The instrument is currently equipped with an electron impact storage ionization source for preparation of a wide variety of molecular cations and anions using suitable neutral precursor gases. Incorporation of an additional ESI ion source is planned.

Closer look

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Spectroscopic studies performed in the past years demonstrate the versatility of the cold ion trap instrument interfaced with FELIX, targeted systems  include:

  • astrophysically important cations, ranging in size from comparatively small systems (e.g., CnHm+, n=1-3, m=0-3; CnHmN+, n=2,3, m=1-6) to larger systems like PAHs (e.g., C10H8+(++), C17H11+)
  • microsolvated ions, e.g. protonated methane (CH5+(H2)n, n=1-3) and halide anions (Cl-H2)
  • weakly bound complexes, e.g. He-O2H+, H2(He)n+, H3O-

Preparations are underway to augment the mass range of FELion for future investigations of larger systems.

Schematic layout and photo of the FELion set-up.

User station 6 schematic layout


The FELion cryogenic ion trap beam line at the FELIX free-electron laser laboratory: infrared signatures of primary alcohol cations.
J. Pavel, S. Brünken, O. Asvany, S. Thorwirth, A. Stoffels, L. van der Meer, G. Berden, B. Redlich, J. Oomens, and S. Schlemmer
Faraday Discussions 217 (2019) 172-202.
© 2019 Royal Society of Chemistry. (pdf file)