Structural and electron spin state changes in an x-ray heated iron carbonate system at the Earth's lower mantle pressures

High-efficiency X-ray emission spectroscopy of cold-compressed Fe2O3and laser-heated pressurized FeCO3using a von Hámos spectrometer

“…Laser-heated FeCO 3 in the given pressure range undergoes a phase transition into Fe 4 3+ C 3 O 12 and Fe 2 2+ Fe 2 3+ C 4 O 13 . 21,35–41 Recently Albers et al 29 and Kaa et al 30 have shown experimentally, that both phases are in HS state. The findings in this study are in accordance with the spin changes for laser-heated FeCO 3 .…”

“…[15][16][17][18][19] Thus, a detailed understanding of the electronic structure of iron-bearing compounds in situ at extreme conditions, i.e., high temperature and high pressure, is crucial to understand and interpret the material's properties and chemistry of the interior of the Earth and other terrestrial planets. Besides Mössbauer spectroscopy [20][21][22] and X-ray absorption spectroscopy, 4,23 X-ray emission spectroscopy, resonant 24,25 and nonresonant, 5,6,[25][26][27][28][29][30] is widely used to determine spin state, covalency, oxidation state, electronic structure and structural changes.…”

A compact von Hámos spectrometer for parallel X-ray Raman scattering and X-ray emission spectroscopy at ID20 of the European Synchrotron Radiation Facility

“…Dispersive X-ray spectrometers in von Ha ´mos geometry exist in many shapes and sizes. Recent developments include specialized setups for multiple emission-line detection experiments (Hayashi et al, 2008;Kalinko et al, 2020), setups at free-electron lasers allowing high and ultrahigh time resolution (Szlachetko et al, 2012;Alonso-Mori et al, 2012a,b) as well as extreme conditions (Kaa et al, 2022), and simple, yet effective, short-working-distance spectrometers Pacold et al, 2012). If requirements to the spectrometer energy resolution are slightly relaxed, high-quality nonresonant XES spectra can be obtained in the laboratory using cylindrically bent highly annealed pyrolitic graphite as analyzer crystals (Anklamm et al, 2014;Malzer et al, 2018;Zimmermann et al, 2020).…”

Hot Measure of Spin States Under Pressure

“…But doing so is tricky because diamond-anvils can deteriorate under the conditions required for these measurements. Now, Johannes Kaa of the Technical University of Dortmund, Germany, and colleagues have demonstrated a way to heat samples to temperatures of up to 3000 K without destroying the diamond-anvils in the process [1].…”

“…Previously, researchers have combined diamond-anvil cells with heat pulses from x-ray free-electron lasers (XFELs) and with Credit: J. Kaa et al [1] x-ray diffraction to study compounds at the conditions found deep inside Earth. But in those experiments they only measured structural properties of the compounds and not quantum ones, which can require that the sample be exposed to high pressures and temperatures for tens of minutes.…”