Mössbauer Spectrometer with Magnet

• Subject Area: Molecular Chemistry
• Term: Funded in 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 424956795

Mössbauer spectroscopy is an element-specific spectroscopy of the states of atomic nuclei, whereby nuclear-electron interactions leads to information also about the electronic states of the addressed atoms. This method of investigation has proved to be particularly valuable and meaningful for iron, and it is therefore of particular importance in the fields of bioinorganic chemistry and bioinspired coordination chemistry, but also for many other fields of science in which iron compounds are studied. Mössbauer spectra recorded in the absence of an external magnetic field usually show a doublet (2-line spectrum) for absorbing iron nuclei. The parameters determined from this (as well as their temperature dependence) provide information about, inter alia, spin and oxidation states of the iron nuclei or molecular dynamics on the Mössbauer time scale, both for solid samples and for frozen solutions. Information far beyond this can be gained from Mössbauer spectra recorded in the presence of an externally applied magnetic field. Here, the 2-line spectrum is split by the Zeeman effect into a 6-line spectrum, which makes visible some very important, more detailed information about the electronic and magnetic structure. Thus, by Mössbauer spectroscopy in a magnetic field the anisotropy parameters, magnetic hyperfine couplings, asymmetry parameters and relaxation times, etc., can be determined, providing deep insights into the objects under investigation. It is exactly these insights that are increasingly important, and in some cases even essential, in several research projects of the applicant's group dealing with biomimetic coordination chemistry, bioinspired catalysis, and iron-based molecular magnets and spin-crossover compounds. A Mössbauer spectrometer equipped with a magnetic field is available only in very few locations in Germany, and there is none in Göttingen until now. By establishing state-of-the-art instrumentation for magnetic field-dependent Mössbauer spectroscopy, the requested device should first and foremost cover the measurement needs of the applicant's group as well as cooperating partner groups. To this end, the requested device will comprise a novel magneto-optic cryostat, which offers exceptional vibration stability and high field homogeneity, and which also allows temperature-dependent measurements under the influence of external physical stimuli such as pressure or light.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Mößbauer-Spektrometer im Magnet-Kryostat
• Instrumentation Group: 0800 Mössbauer-Meßplätze
• Applicant Institution: Georg-August-Universität Göttingen
• Leader: Professor Dr. Franc Meyer