THz spectroscopy & THz EPR
sub mm wave / THz Spectroscopy THz Electron Paramagentic Resonance at THz Beamline
Motivation
Main science drivers are investigations in spin coupling energies of high-spin transition metal and rare earth ions. Spin coupling energies are sensitive probes of the electronic structure and determine magnetic properties of compounds with unpaired electron spins. The latter are highly desired pieces of information, as high-spin paramagnetic ions determine the function of many vital catalytic processes in proteins and synthetic complexes, as well as the properties of systems with large exchange couplings, e.g. single-molecule magnets (SMMs), energy materials or strongly correlated solids.
Frequency-Domain Fourier-Transform THz-EPR (FD-FT THz-EPR)
EPR is capable of providing unique information on magnetic structure-function relationships of materials containing unpaired electron spins. However, conventional single frequency EPR frequently fails in cases where spin transition energies exceed the quantum energy of the spectrometer (typically <4 cm-1). Employing very short electron bunches (low-α), we have demonstrated that coherent synchrotron radiation (CSR) [1, 2]-based FD-FT THz-EPR [3] provides a unique tool to overcome this restriction. Our approach allows for EPR excitations over a broad energy (3 cm-1 – 370 cm-1) and magnetic field range (-11 T – +11 T) in a single spectrometer. FD-FT THz-EPR has been successfully applied to high-spin ions in SMMs [4], single-chain magnets (SCMs) [5], catalytically relevant mononuclear integer and non-integer high-spin transition metal ion complexes [6, 7], as well as in proteins [8] and strongly correlated solid-state systems [9].
Methods
Time-resolved studies, IR Spectroscopy
Assigned to beamline(s)
| Energy range | Polarisation | |
|---|---|---|
| THz-Beamline | 5 1/cm 10000 1/cm | variable |
| Station data | |
|---|---|
| Temperature range | 1.6-300 K |
| Pressure Range | For details contact the station scientist. |
| Detector | 1.6 K (pumped) and 4.2K Si-Bolometer, InSb-HEB, DTGS, Ultrafast Schottky Diode (ACST) |
| Manipulators | Sample VTI in OXFORD Magnet Spectromag 4000 |
| Sample holder compatibility | For details contact the station scientist. |
| Resolution | 0.0063 1/cm |
| Magnetic field | +/- 11 Tesla |
References
[1] M. Abo-Bakr, et al. Phys. Rev. Lett., 2003, 90, 094801.
[2] K. Holldack, et al. Phys. Rev. Lett., 2006, 96, 054801.
[3] J. Nehrkorn, et al. J. Magn. Reson., 2017, 280, 43739.
[4] D. Pinkowicz, et al. J. Am. Chem. Soc., 2015, 137, 14406.
[5] M. Rams, et al. Chem. Eur. J., 2020, 26, 2837.
[6] J. Nehrkorn, et al. Inorg. Chem., 2019, 58, 14228.
[7] J. Krzystek, et al. Inorg. Chem., 2020, 59, 1075.