Group ESR Spectroscopy

My group uses Electron Paramagnetic Resonance (EPR) also known as Electron Spin Resonance (ESR) Spectroscopy to investigate the structure of novel materials and proteins. Our work is unashamedly collaborative and brings together biologists, chemists, materials scientists and physicists.

What is EPR spectroscopy?
EPR spectroscopy is a powerful technique, giving insights into the structure of materials/molecules and proteins. Paramagnetic substances like e.g., unpaired electron spins of radicals, are exposed to a magnetic field to tune the zeeman splitting between the two possible spin states. Subsequently, the resulting energy transitions get probed by microwave (MW) irradiation. Generally, a distinction between two modes of operation is made: Continuous wave (CW) and pulsed MW irradiation.
Both methods incooperate distinct spectral features which can give answers to different structural investigation issues. Our work is widely collaborative and brings together biologists, chemists, materials scientists and physicists.

Structural Biology

Combining X-ray crystallography, molecular dynamics and nitroxide spin-labeling EPR spectroscopy to obtain and verify structures of proteins in solution (Ilangovan et al, Cell 2017, Bagneris et al Nature Communications 2013, Webster et al Nucleic Acids Research 2012, Phan et al Nature, 2011, Grohmann et al Journal of the American Chemical Society 2010).

Room Temperature MASERs

The MASER (Microwave Amplification by Stimulated Emission of Radiation) is the forerunner of the Laser, but is less well know and developed due to technical challenges. Recently, together with colleagues at Imperial College London, we have been developing a MASER based on the lowest excited triplet state of pentacene in p-terphenyl (Salvadori et al, Scientific Reports 2017, Breeze et al, Quantum Information 2017) and NV- centres in diamond that works at room temperature (Breeze et al, Nature 2018).

Research works

Current theses in the working group of ESR spectroscopy:

Halbach Magnet for Masers

High Performance resonators for Room Temperature Masers

Pulse Shaping for EPR

EPR studies on a Ni3 complex


Low Temperature Characterization of a Maser

If you are interested in a thesis, please contact the listed supervisor or just drop by. If there is no thesis listed, but you are interested in EPR spectroscopy, we can discuss individual theses.

Completed scientific papers (bachelor and master theses) and doctoral theses are listed below.

Scientific theses


  • Synthesis and Characterization of Dithiadiazolyl Radicals
    (Tiziano Caldara, September 2023)
  • Investigation on the photo-excited triplet state of Porphycene by ESR- and ENDOR-spectroscopy
    (Maxim Neuberger, August 2022)
  • Eigenschaften von phosphonium-basierten ionischen Flüssigkeiten mit symmetrischen Ionen
    (Daniel Schroeder, August 2022)
  • Untersuchung der Triplettzuständen sternförmiger Tetrathiofulvalen-Oligofluoren Systeme mittels TREPR-Spektroskopie und DFT-Rechnungen
    (Lukas Schank, September 2021)
  • Die Untersuchung organischer Perylenfarbstoffe in Polysiloxanen-Matrices mittels TREPR-Spektroskopie
    (Lukas Schneider, April 2021)
  • Developments of methods to automate Masing threshold determination
    (Yan Fett, April 2021)
  • Analyse potentiell geeigneter Moleküle für singlet-fission mittels EPR-Spektroskopie
    (David Schaaf, März 2021)
  • Optimierung der stimulierten Emission bei den Stickstoff-Leerstellen eines Diamanten
    (Haakon Wiedemann, September 2018)



  • Hyperfine analysis of Cu zeolites for use in catalysis in diesel engines
    (David Schaaf, April 2023)
  • Optimierung der FT-ICR-MS Detektion und Charakterisierung einzelsträngiger DNA-Oligonucleotiden-Modellkomponenten mit Direktinjektion und gekoppelter HPLC mit jeweiliger Tandem-Massenspektrometrie
    (Philip Jochum, August 2022)
  • EPR- und ENDOR-Spektroskopie an angeregten Triplettzuständen
    (Elias Gießelmann, Dezember 2021)
  • Nitrogen transfer reactions with (Bis)iminophosphoranes and Palladium Nitrenes
    (Djana Momper, Dezember 2021)
  • Wege zum Hochleistungs-EPR-Resonator
    (Haakon Wiedemann, Juli 2021)
  • Photo-excited singlet and triplet states of Reichhardts dye in glass-forming ionic liquids
    (Ramona Jost, März 2021)
  • Spin-polarisation in a stable radical covalently linked to a dye molecule
    (Johannes Krämer, Oktober 2020)
PhD theses

Group ESR Spectroscopy

Group Leader

Prof. Dr. Christopher W. M. Kay

Chair und Group Leader of ESR Spectroscopy

Building B2 2 Room 0.24
Tel:  +49 681 302 2213
Fax: +49 681 302  4759

(... more)


Team Assistant/Secretary

Petra Theobald

Building B2 2 Room 0.22
Tel:  +49 681 302 2473
Fax: +49 681 302 4759



Scientific Staff

Dr. Yi Dong

Geb. B2 2
Tel:  +49 681 302 64310



Haakon Wiedemann, M.Sc.

PhD student

Geb. B2 2 Raum 0.21
Tel:  +49 681 302 2741 



Dipl.-Chem. Dina Klippert

PhD student

Geb. B2 2
Tel:  +49 681 302 64310


Dr. Christoph Zollitsch


Geb. B2 2 Raum 0.21 
Tel.: +49 681 302 9002767

(... more)


Stefan Ruloff, M.Sc.

PhD student

Geb. B2 2 Raum 0.25
Tel:  +49 681 302 64245


Student Members

Jonas Bach, B.Sc.

Chemistry (Master)

Synthesis and EPR spectroscopy


Wilma Koblé

Chemistry (Bachelor)

Support of courses: Pre-course


Maxim Neuberger, B.Sc.

Chemistry (Master)

EPR spectroscopy
Support of courses: PCF


Robin Pilger

Lehramt Sek I / II (Chemistry, Biology)

Support of courses: PC02, Trial Study


Ruwen Schank

Chemistry (Bachelor)

EPR spectroscopy
Support of courses: PCF


Daniel Schroeder, B.Sc.

Chemistry (Master)

Support of courses: PCF


Eva Steuer

MINT (Bachelor-focus Chemistry)

EPR spectroscopy
Social Media/ Homepage




Dr. Daniel Rauber

Dr. Clemens Matt

Dr. Till Biskup

M.Sc. Phillip Jochum

M.Sc. Elias Gießelmann

M.Sc. Mirjam Schröder

M.Sc. Ramona Jost