Iron dynamics in earth mantle minerals probed by Mössbauer spectroscopy using synchrotron radiation

• Applicant: Professor Dr. Volker Schünemann
• Subject Area: Mineralogy, Petrology and Geochemistry
• Term: from 2006 to 2010
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 24982785

Exploring the dynamic properties of iron minerals contained in the earth mantle enables to understand seismologic data on the microscopic scale. Mössbauer spectroscopy is the method of choice if electronic and dynamic properties of iron containing minerals have to be investigated. We therefore propose to measure the dynamic properties of the iron containing minerals olivine, pyroxene, iron silicate perovskite and ferropericlase by Mössbauer spectroscopy under high-pressure with synchrotron radiation. Nuclear inelastic scattering (NIS) and accompanying quantum mechanical model calculations employing density functional theory (DFT) will deliver the phonon density of states of the minerals under investigation both experimentally and theoretically. In this way we will obtain information on the velocity of sound in these materials under high pressure conditions. Parallel to the NIS experiments we will perform nuclear forward scattering (NFS) which will yield information on the iron valence state and the corresponding iron mineral phases. This is especially interesting in the region of phase transitions which are responsible for discontinuities in the seismic response of the earth mantle.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1236: Synthesis, "In Situ" Characterisation and Quantum Mechanical Modelling of Earth Materials, Oxides, Carbides and Nitrides at Extremely High Pressures and Temperatures