Education, Honors, Awards
- Assistant Professor, James Madison University (2008-present)
- Visiting Assistant Professor, James Madison University (2006-2008)
- Adjunct Assistant Professor and Researcher, University of California, Los Angeles (2004-06)
- Postdoctoral Fellow, Museum of Natural History, Smithsonian Institution (2003-04)
- Ph.D. California Institute of Technology (2003)
- M.S. California Institute of Technology (1999)
- B.A. Rice University (1997)
- Infrared and nuclear magnetic resonance spectroscopy of hydrous species in minerals and anisotropic solids
- Diffusion behavior of hydrous species in minerals
- Thermally-induced structural changes in synthetic cation-exchanged birnessite
- The role of magmatic water in volcanic eruptions
I study interactions between the hydrosphere (water) and the lithosphere (solid materials that make up Earth). Some of my current and recent projects include:
- Evaluating the role of magmatic water in the explosive eruptions of Mount St. Helens using structurally-bound hydroxyl in the mineral feldspar;
- Determining the rate and mechanism of diffusion of hydrogen through the feldspar crystal structure (will the hydroxyl be retained in the feldspar during eruption?);
- Using the crystal chemistry of rutile (TiO2) to determine the oxidation state of piston-cylinder experiments, subduction zones and the ancient crust;
- Learning about the structure and stability of interlayer water molecules in birnessite (Mn oxide). Birnessite-type materials are used in industrial oxidation-reduction reactions and lithium manganese oxides are used as cathodes in Li-ion batteries.
The principal tool I use in my research is infrared spectroscopy. Infrared spectroscopy is sensitive to the vibrations of hydrous species (H2O, OH, and NH4+, for example) and can be used to quantify the amount of hydrous species in as well learn about the bonding environment of hydrogen in a solid. Other analytic tools I have used in my research include electron and ion microscopy, nuclear magnetic resonance spectroscopy, Raman spectroscopy, and optical spectroscopy.
Selected Recent Publications
- Johnson, E.A. and Rossman, G.R. (Submitted) Diffusion of hydrogen in plagioclase feldspar. Geochimica et Cosmochimica Acta.
- Johnson, E.A. (2006) Water in nominally anhydrous crustal minerals: speciation, concentration, and geologic significance. In H. Keppler and J.R. Smith (Eds.) Water in Nominally Anhydrous Minerals. Reviews in Mineralogy and Geochemistry, 62, 117-154.
- Johnson, E.A. and Post, J.E. (2006) Water in the interlayer of the Mn oxide birnessite: importance in cation exchange and structural stability. American Mineralogist, 91, 609-618.
- Johnson, E.A. and Rossman, G.R. (2004) An infrared and nuclear magnetic resonance study of strong hydrogen bonding in ussingite, NaAlSi3O8(NaOH). Physics and Chemistry of Minerals, 31, 115-121.
- Johnson, E.A. and Rossman, G.R. (2004) A survey of hydrous species and concentrations in igneous feldspars. American Mineralogist, 89, 586-599.
- King, J.L., Johnson, E.A., and Post, J.E. (2003) A comparison of three historic blue diamonds. Gems and Gemology, 39(4), 322-325.
- Johnson, E.A. and Rossman, G.R. (2003) The concentration and speciation of hydrogen in feldspars using FTIR and 1H MAS NMR spectroscopy. American Mineralogist, 88, 901-911.
- Johnson, E.A., Rossman, G.R., Dyar, M.D., and Valley, J.W. (2002) Correlation between OH concentration and oxygen isotope diffusion rate in diopsides from the Adirondack Mountains, New York. American Mineralogist, 87, 899-908.