Postdoctoral Researcher, IDREAM
Postdoctoral Researcher, IDREAM


Sebastian Mergelsberg joined Pacific Northwest National Laboratory (PNNL) in 2020 and is a postdoctoral researcher interested in the controls governing nucleation and growth of minerals. He also has interests in the chemical and structural signatures associated with select pathways of mineral formation. He is currently performing research with the Interfacial Dynamics in Radioactive Environments and Materials (IDREAM) Early Career Network.

Specifically, Mergelsberg works to measure the structure and composition of amorphous and crystalline metal carbonate phases, as well as crystalline iron oxyhydroxides, in situ using high-energy X-ray and spectroscopic analysis methods. Results will provide a quantitative basis for the sensitivity of energy landscapes to solution composition for a wide range of Earth materials.

Research Interest

  • Coordination changes in mineral transformations
  • Solvent dynamics
  • Chemical reactivity
  • Solute organization
  • Pre-nucleation species in highly alkaline systems
  • Pulsed field gradient nuclear magnetic resonance diffusometry
  • Quadrupolar nuclei

Disciplines and Skills

  • Aggregation
  • Analytical chemistry
  • Carbonates
  • Experimental design
  • Geochemistry
  • Inorganic chemistry
  • Inorganic synthesis
  • Kinetic modeling
  • Kinetics
  • Nucleation
  • Phosphate
  • Powder X-ray diffraction
  • Python
  • Raman spectroscopy
  • Scanning electron microscopy
  • Small angle X-ray scattering (SAXS)
  • Solubility
  • Structure determination
  • Thermodynamic modeling
  • X-ray crystallography, diffraction, and analysis; pair distribution function analysis


  • PhD, Geosciences, Virginia Polytechnic Institute & State University
  • BS, Geology, Rensselaer Polytechnic Institute



  • Avalos N.M., T. Varga, S.T. Mergelsberg, J.A. Silverstein, and S.A. Saslow. 2021. "Behavior of iodate substituted ettringite during aqueous leaching." Applied Geochemistry 125. PNNL-SA-152089. doi:10.1016/j.apgeochem.2020.104863
  • Gillispie E.C., S.T. Mergelsberg, T. Varga, S.M. Webb, N.M. Avalos, M. Snyder, and A. Bourchy, et al. 2021. "Competitive TcO4-, IO3-, and CrO42- Incorporation into Ettringite." Environmental Science & Technology 55, no. 2:1057-1066. PNNL-SA-151816. doi:10.1021/acs.est.0c06707
  • Graham T.R., M. Dembowski, H. Wang, S.T. Mergelsberg, E.T. Nienhuis-Marcial, J.G. Reynolds, and C.H. Delegard, et al. 2021. "Hydroxide promotes ion pairing in the NaNO2-NaOH-H2O system." Physical Chemistry Chemical Physics 23, no. 1:112-122. PNNL-SA-156222. doi:10.1039/D0CP04799F
  • Mergelsberg S.T., M.P. Prange, D. Song, E.J. Bylaska, S.A. Saslow, J.G. Catalano, and E.S. Ilton. 2021. "Resolving Configurational Disorder for Impurities in a Low Entropy Phase." Journal of Physical Chemistry Letters 12, no. 24:5689-5694. PNNL-SA-161096. doi:10.1021/acs.jpclett.1c01218
  • Mergelsberg S.T., S.L. Riechers, T.R. Graham, M.P. Prange, and S.N. Kerisit. 2021. "Effect of Cd on the Nucleation and Transformation of Amorphous Calcium Carbonate." Crystal Growth & Design 21, no. 6:3384-3393. PNNL-SA-159457. doi:10.1021/acs.cgd.1c00169
  • Prange M.P., S.T. Mergelsberg, and S.N. Kerisit. 2021. "Ab Initio Molecular Dynamics Simulations of Amorphous Calcium Carbonate: Interpretation of Pair Distribution Function and X-Ray Absorption Spectroscopy Data." Crystal Growth & Design 21, no. 4:2212-2221. PNNL-SA-158427. doi:10.1021/acs.cgd.0c01655


  • Hammond-Pereira E., K. Bryant, T.R. Graham, C. Yang, S.T. Mergelsberg, D. Wu, and S.R. Saunders. 2020. "Mesoporous silica-encapsulated gold core-shell nanoparticles for active solvent-free benzyl alcohol oxidation." Reaction Chemistry & Engineering 5, no. 10:1939-1949. PNNL-SA-151451. doi:10.1039/D0RE00198H
  • Huestis P.I., T.R. Graham, S.T. Mergelsberg, and J.A. LaVerne. 2020. "Identification of Radiolytically-Active Thermal Transition Phases in Boehmite." Thermochimica Acta 689. PNNL-SA-151694. doi:10.1016/j.tca.2020.178611
  • Ilton E.S., L. Kovarik, E. Nakouzi, S.T. Mergelsberg, M.E. McBriarty, and E.J. Bylaska. 2020. "Using Atom Dynamics to Map the Defect Structure Around an Impurity in Nano-Hematite." Journal of Physical Chemistry Letters 11, no. 24:10396-10400. PNNL-SA-153756. doi:10.1021/acs.jpclett.0c02798
  • Mergelsberg S.T., J.J. De Yoreo, Q. Miller, F.M. Michel, R. Ulrich, P.M. Dove, and P.M. Dove. 2020. "Metastable solubility and local structure of amorphous calcium carbonate (ACC)." Geochimica et Cosmochimica Acta 289. PNNL-SA-160781. doi:10.1016/j.gca.2020.06.030
  • Mergelsberg S.T., S.N. Kerisit, E.S. Ilton, O. Qafoku, C.J. Thompson, and J.S. Loring. 2020. "Low Temperature and Limited Water Activity Reveal a Pathway to Magnesite via Amorphous Magnesium Carbonate." Chemical Communications 56, no. 81:12154-12157. PNNL-SA-154304. doi:10.1039/D0CC04907G
  • Saslow S.A., S.N. Kerisit, T. Varga, S.T. Mergelsberg, C.L. Corkhill, M. Snyder, and N.M. Avalos, et al. 2020. "Immobilizing Pertechnetate in Ettringite via Sulfate Substitution." Environmental Science & Technology 54, no. 21:13610-13618. PNNL-SA-147963. doi:10.1021/acs.est.0c03119


  • Bylaska E.J., J.G. Catalano, S.T. Mergelsberg, S.A. Saslow, O. Qafoku, M.P. Prange, and E.S. Ilton. 2019. "Association of Defects and Zinc in Hematite." Environmental Science & Technology 53, no. 23:13687-13694. PNNL-SA-144849. doi:10.1021/acs.est.9b04323