HFML-FELIX Laboratory (Nijmegen, the Netherlands)

Stichting Radboud Universiteit, Radboud University, Nijmegen

HFML-FELIX is a renowned national research institute, located in Nijmegen, the Netherlands. The institute houses the High-Field Magnet Laboratory (HFML) and Free-Electron Lasers for Infrared eXperiments (FELIX) that enable scientists from all over the world to expose matter to extreme conditions and drive it into previously inaccessible states and phases. It is also the only lab in the world where these two techniques can be combined, making it a unique research facility.
The FELIX Laboratory focuses on the development and exploitation of advanced infrared and THz sources. It comprises a number of groups with complementary expertise in the application of infrared and THz radiation e.g. (bio)molecular physics, solid-state physics and soft condensed matter.

The FELIX Laboratory exploits intense, short-pulsed infrared and THz free-electron lasers that are used for the research of matter both by in-house as well as national and international external users. The four lasers FELIX-1, FELIX-2, FELICE and FLARE each produce their own range of wavelengths and together, they provide a tuning range between 3 and 1500 µm.

The infrared radiation of the FELIX lasers interacts with molecules and materials. This can reveal detailed information about 3D structure, functional properties and electronic properties. The local research program is executed in several groups: FELIX Infrared and THz Spectroscopy; FELIX FEL Technology; Condensed Matter Physics and Molecular Structure and Dynamics.

The FELIX Laboratory is a large facility that is open for external users with projects selected by the Programme Advisory Committee. Very regular users maintain their own (more or less) permanent set-ups which may also be used by external users.

Website: https://hfml-felix.com/

Contact: Andrei Kirilyuk

Research highlights

The institute uses the radiation of free electron laser FELIX to study both static and dynamic properties of matter.

Researchers at HFML-FELIX succeeded in determining the infrared fingerprint for this protonated form (C60 H+). Thanks to new measurements they can now add even more detail to this, which should make it a lot easier to detect the molecule in space.
L. Finazzi, V.J. Esposito, J. Palotás, J. Martens, E. Peeters, J. Cami, G. Berden, and J. Oomens, Experimental Determination of the Unusual CH Stretch Frequency of Protonated Fullerenes, Astrophys. J. 971, 168 (2024).

We reported far-infrared spectrum of isolated neutral S8, under the cold and isolated conditions of a molecular beam. The experimental spectra of the investigated species show a remarkably good agreement with computational modelling, enabling us to predict lower abundance limits for their astronomical detection using the James Webb Space Telescope.
P. Ferrari, G. Berden, B. Redlich, L.B.F.M. Waters & J.M. Bakker, Laboratory infrared spectra and fragmentation chemistry of sulfur allotropes, Nature Commun. 15, 5928 (2024)

In this project we identify the most probable binding position of a vanadium cation on C60 above a pentagon center, demonstrate a high thermal stability for this complex, and explore the bonding nature between C60 and the vanadium cation, revealing that large orbital and electrostatic interactions lie at the origin of the stability of the C60V+ complex. (with users from KU Leuven, Belgium)
J. Xu, J.M. Bakker, O.V. Lushchikova, P. Lievens, E. Janssens, & G.-L. Hou, Pentagon, Hexagon, or Bridge? Identifying the Location of a Single Vanadium Cation on Buckminsterfullerene Surface, J. Am. Chem. Soc. 145, 22243 (2023).

Our team devised a creative approach to switch magnetization, based on the ultrafast analogue of the Barnett effect. Using infrared pulses of light from the free-electron lasers at FELIX, we drive circular vibrations of the substrate lattice. The substrate then becomes magnetic for a few picoseconds, flipping the magnetization of a thin layer mounted on top of it. (with users from Institute for Molecules and Materials, Radboud University)
C.S. Davies, F.G.N. Fennema, A. Tsukamoto, I. Razdolski, A.V. Kimel and A. Kirilyuk, Phononic switching of magnetization by the ultrafast Barnett effect, Nature 628, 540 (2024).

We have recently demonstrated that an ultrafast excitation in the infrared range can induce permanent all-optical reversal of ferroelectric polarization between different stable states. For this we relied on very specific optical properties that naturally emerge from the solid’s ionic lattice resulting in the demonstrated mechanism of reversal being truly universal, capable of permanently switching order parameters in a wide variety of systems.
M. Kwaaitaal, D. G. Lourens, C. S. Davies & A. Kirilyuk, Epsilon-near-zero regime enables permanent ultrafast all-optical reversal of ferroelectric polarization, Nature Photonics 18, 569 (2024).

Expertise

Understanding the perplexing links between the quantum domain of individual atoms and the macroscopic world around us represents a monumental challenge in — but not limited to — physics and chemistry. The research agenda of HFML-FELIX aims to solve these grand challenges by studying fascinating phenomena at the detection and resolution limits available. Harnessing some of the unprecedented wavelength span and pulse energies of the suite of free-electron lasers, also in a combination with the world’s highest continuous magnetic fields are the key to discover, visualise, characterise and comprehend, for example, unidentified molecular structures and novel phases of matter.

The following topics broadly represent the research alignment and starting point of the new institution. This has been defined in close collaboration with the HFML-FELIX research team and the Institute for Molecules and Materials (IMM, Radboud University) and includes the many ongoing collaborations with national partners.

Overview of the research and engineering topic lines

  1. Mapping and manipulating quantum phases of matter  
  2. Non-equilibrium phases of matter
  3. Dynamic self-organisation in soft molecular matter: Fundamental insights from extreme conditions
  4. Molecular structure identification and reactivity using advanced infrared spectroscopy
  5. Innovative instruments for advanced spectroscopy in high magnetic fields and with intense infrared/THz light
Equipment offered to external users

We house a suite of four free-electron lasers that produce (far) infrared light with an unprecedented tuning range and very high intensity. The infrared radiation of the lasers interacts with molecules and materials, which can reveal detailed information about their 3D structure, functional properties, and electronic properties. Cutting-edge research like this contributes significantly to the understanding of new functional materials, (bio)molecules and processes relevant to catalysis and astrochemistry.

In particular, for molecular spectroscopy, a range of mass spectrometers (linear ion traps, Fourier transform ion cyclotron resonance, time-of-flight) is available, equipped with a variety of sources (electrospray, ACPI, laser vaporization, laser desorption, electron impact) that allow the volatilization of virtually any molecular compound, ranging from small molecules in solution to large aromatic and inorganic clusters. Most instruments are operating at room temperature, several allow cryogenic operation down to temperatures of 10 K. Each of these instruments is coupled to the free-electron lasers allowing the most sensitive spectroscopic characterization of analytes under study.

For condensed matter physics direction, ultrafast spectroscopic techniques are available, including both single-colour and two-colour pump-probe techniques, with the possibilities of applying low temperatures and high magnetic fields. Visible femtosecond-range lasers are synchronized to the FELs, allowing for time resolution down to sub-picosecond range.