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.

Research

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).

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).

Research works

Research papers on the following main topics can be written in the working group of ESR spectroscopy:

High power resonators for room temperature masers, spin traps, ENDOR spectroscopy on atomic hydrogen, transient ESR on porphyrin/porphycene derivatives, ...

If you are interested in research work, please contact H. Wiedemann.

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

Bachelor-theses:

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

Master-theses:

Optimierung der FT-ICR-MS Detektion und Charakterisierung einzelsträngiger DNA-Oligonucleotiden-Modellkomponenten mit Direktinjektion und gekoppelter HPLC mit jeweiliger Tandem-Massenspektrometrie
(P. Jochum, August 2022)
EPR- und ENDOR-Spektroskopie an angeregten Triplettzuständen
(E. Gießelmann, Dezember 2021)
Nitrogen transfer reactions with (Bis)iminophosphoranes and Palladium Nitrenes
(D. Momper, Dezember 2021)
Wege zum Hochleistungs-EPR-Resonator
(H. Wiedemann, Juli 2021)
Photo-excited singlet and triplet states of Reichhardts dye in glass-forming ionic liquids
(R. Jost, März 2021)
Spin-polarisation in a stable radical covalently linked to a dye molecule
(J. Krämer, Oktober 2020)