Mössbauer Spectroscopy - Pennsylvania State University

M?ssbauer Spectroscopy

Carsten Krebs Department of Chemistry Department of Biochemistry and Molecular Biology The Pennsylvania State University

Recommended Literature

P. G?tlich, E. Bill, A. X. Trautwein "M?ssbauer Spectroscopy and Transition Metal Chemistry" Springer, 2011

E. M?nck "Aspects of 57Fe M?ssbauer Spectroscopy" Chapter 6 in Physical Methods in Bioinorganic Chemistry L. Que, Jr. (editor) University Science Books, 2000

Outline

? General remarks ? Quadrupole doublet spectra (isomer shift, quadrupole splitting) ? Magnetically split spectra (spin expectation value, hyperfine tensor) ? The correlation between EPR and M?ssbauer spectroscopies

(effective g-values and spin expectation values) ? How is the internal field oriented relative to the external field? ? How does the fluctuation rate of the electronic states affect the M?ssbauer spectrum? ? Example 1: EPR and M?ssbauer of the high-spin Fe(III) center in transferrin ? Example 2: EPR and M?ssbauer of the Fe(II)/Fe(III) cluster in myo-inositol oxygenase

(incl. magnetic M?ssbauer of dinuclear clusters) ? Example 3: M?ssbauer studies of the Fe(III)/Fe(III) cluster E. coli RNR ? Example 4: The high-spin Fe(IV)-oxo intermediate in TauD ? Example 5: A mononuclear Fe-dinitrosyl complex with S = 1/2 ? Considerations for sample preparation

The Electromagnetic Spectrum

Recoil Effect in "Free" Atoms

recoil energy: ER = E02 / 2Mc2

nucleus -photon

M

E = Enuc - ER

ER 5-6 orders of magnitude greater than natural linewidth no resonance possible

=> Nuclear -Resonance cannot be observed with gases and liquids !

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