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With a background in experimental physics and in computational chemistry Sandro Jahn specialized in atomic-scale modeling of geological materials and processes. His scientific interests include the physical and thermodynamic properties of minerals, oxide and silicate liquids and glasses as well as aqueous fluids at pressure and temperature conditions ranging from the Earth’s surface to its deep interior. Using classical and quantum-mechanical simulation approaches, he applies and develops accurate and predictive computational methods that link the electronic and molecular structures of complex materials to their macroscopic properties. The combination of density-functional theory calculations with the molecular dynamics simulation method, so-called first-principles or ab initio molecular dynamics simulations require substantial computing power and are only feasible using high performance computing resources. Most of the numerical simulation activities are inspired and complemented by experiments. The research group therefore also operates a high-pressure/high-temperature experimental laboratory with diamond anvil cells and Raman spectroscopy. Other experiments are performed at synchrotron radiation facilities. For more details about research activities and publications, see http://www.geologie.uni-koeln.de/2397.html.

Snapshots from first-principles molecular dynamics simulations of SiO2 melt/glass at a temperature of 4000 K and densities of 2.66, 4.40 and 7.0 g/cm3 (Prescher et al. 2017). Si coordination environments are colored: 4 – orange, 5 – green, 6 – grey, 7 – red, 8 – blue.

Selected publications

  1. Prescher, C., Prakapenka, V. B., Stefanski, J., Jahn, S., Skinner, L. B., Wang, Y., 2017. Beyond sixfold coordinated Si in SiO2 glass at ultrahigh pressures, PNAS 114, 10041-10046.
  2. Wagner, J., Künzel, D., Haigis, V., Jahn, S., 2017. Trace element partitioning between silicate melts - a molecular dynamics approach, Geochim. Cosmochim. Acta 205, 245-255.
  3. Sahle, C. J., Sternemann, C., Schmidt, C., Lehtola, S., Jahn, S., Simonelli, L., Huotari, S., Hakala, M., Pylkkänen, T., Nyrow, A., Mende, K., Tolan, M., Hämäläinen, K., Wilke, M., 2013. Microscopic structure of water at elevated pressures and temperatures, PNAS 110, 6301-6306.
  4. Kowalski, P. M., Wunder, B., Jahn, S., 2013. Ab initio prediction of equilibrium boron isotope fractionation between minerals and aqueous fluids at high P and T, Geochim. Cosmochim. Acta 101, 285-301.
  5. Drewitt, J. W. E., Hennet, L., Zeidler, A., Jahn, S., Salmon, P. S., Neuville, D. R., Fischer, H. E., 2012. Structural transformations on vitrification in the fragile glass forming system CaAl2O4, Phys. Rev. Lett. 109, 235501.
  6. Spiekermann, G., Steele-MacInnis, M., Schmidt, C., Jahn, S., 2012. Vibrational mode frequencies of silica species in SiO2-H2O liquids and glasses from ab initio molecular dynamics, J. Chem. Phys. 136, 154501.
  7. Jahn, S., Schmidt, C., 2010. Speciation in aqueous MgSO4 fluids at high pressures and high temperatures from ab initio molecular dynamics and Raman spectroscopy, J. Phys. Chem. B 114, 15565-15572.
  8. Jahn, S., Wunder, B., 2009. Lithium speciation in aqueous fluids at high P and T studied by ab initio molecular dynamics and consequences for Li-isotope fractionation between minerals and fluids, Geochim. Cosmochim. Acta 73, 5428-5434.
  9. Jahn, S., 2008. High-pressure phase transitions in MgSiO3 orthoenstatite studied by atomistic computer simulation, Am. Mineral. 93, 528-532.
  10. Jahn, S., Madden, P. A., 2007. Modeling Earth materials from crustal to lower mantle conditions: A transferable set of interaction potentials for the CMAS system, Phys. Earth Planet. Int. 162, 129-139.