Cirriculum Vitae

PROFESSIONAL EXPERIENCE

2024 – present Postdoctoral Scholar Research Associate in Geochemistry, Caltech – Pasadena, California

Investigations of the hydride (H-) ion in oxide-based materials as a possible “invisible” hydrogen reservoir in planetary interiors. Special focus on Ti perovskites, studied via spectroscopic and quantum mechanics (QM) calculations. My current projects include:

·  Introduction of H- into natural perovskite (CaTiO3) - A study aiming to spectroscopically characterize H- doped perovskite crystals with anticipated application to high-pressure Ca(Si,Ti)O3 perovskite phases.

· Advanced spectroscopic characterization of hydride-doped SrTiO3­ – A detailed look at unusual spectroscopic behaviors associated with H- incorporation that implicate defect chemistry and electronic properties.

EDUCATION 

2019 – 2024    Ph.D. Geochemistry, Caltech – Pasadena, California

Thesis advisor: George Rossman

Thesis title: Hydrogen Incorporation in Rutile- and Perovskite-Structured Minerals and Their Analogues 

I used a combination of QM calculations and vibrational spectroscopy to determine the structural state of hydrogen in materials relevant to planetary interiors. Complimentary methods included UV-vis spectroscopy, 1H NMR, and EPR. My Ph.D. work falls into three categories:

1. Predicting yet-observed hydrogen defects in NAMs via QM: Sometimes, chemical data may suggest the presence of H when no explicit measurement of H is made (i.e., low oxide totals, compositions that do not charge balance). In these cases, QM can be used to predict how H may behave if it is present.

2. Interpreting vibrational spectra via QM: Infrared spectra are inherently tied to the structures of OH- defects in nominally anhydrous phases but cannot be directly interpreted. Through QM calculations, I linked defect structures to spectral features, both in my own data and data from the literature.

3. Exploring the prevalence of H- in oxide phases: H- is documented in a variety of oxide phases but is under-investigated from an earth science perspective. Little has been done to characterize the infrared behavior of H-, because its vibrational modes are in highly absorbing regions of most infrared spectra. I studied H- in rutile-type TiO2 and SrTiO3 perovskite via laboratory and computational methods.

2017 – 2019 M.Sc. Geology at Caltech – Pasadena, California

2013 – 2017 B.S. Geosciences at Virginia Tech – Blacksburg, Virginia 

PUBLICATIONS 

W. R. Palfey, S.J. Hwang, W. A. Goddard III, G. R. Rossman (2024) The spectroscopy of hydride in single crystals of SrTiO3 perovskite. J. Phys. Chem. Chem. Phys. DOI: 10.1039/D4CP02852J

W. R. Palfey, G. R. Rossman, W. A. Goddard III, (2023) Behavior of hydrogarnet‐type defects in hydrous stishovite at various temperatures and pressures. JGR Solid Earth. DOI: 10.1029/2022JB024980

W. R. Palfey, G. R. Rossman, W. A. Goddard III, (2021) Structure, Energetics, and Spectra for the Oxygen Vacancy in Rutile: Prominence of the Ti−HO−Ti Bond. J. Phys. Chem. Lett. DOI: 10.1021/acs.jpclett.1c02850

WORKS IN PREPARATION 

W. R. Palfey, G. R. Rossman, W. A. Goddard III, (In preparation) First-principles study of Na and K coupling to H in davemaoite

O. A. Pardo, W. R. Palfey, V. V. Dobrosavljevic, W. Sturhahn, Z. Liu, W. A. Goddard III, G. R. Rossman, T. S. Toellner, J. M. Jackson (In preparation) High pressure vibrational properties of szomolnokite.

W. R. Palfey, W. A. Goddard III, S. Hwang, G. R. Rossman (In preparation) Characterization of H defects in reduced rutile via infrared and 1H NMR spectroscopy

PRESENTATIONS 

W. R. Palfey, S.J. Hwang, W. A. Goddard III, G. R. Rossman (2024, August) The spectroscopy of hydride in perovskites. Presented at the European Mineralogical Conference, 2024.

W. R. Palfey, The spectroscopy of hydride in SrTiO3 perovskites (2024, February) UCLA Geocheminar (invited).

W. R. Palfey, S.J. Hwang, W. A. Goddard III, G. R. Rossman (2023, December) Hydride in perovskites – a possible mechanism for incorporating hydrogen in the deep earth. Presented at Fall meeting of the American Geophysical Union, 2023.

W. R. Palfey, W. A. Goddard III, S.J. Hwang, G. R. Rossman (2022, December) Hydride in oxide minerals – a potentially overlooked reservoir for hydrogen in the mantle. Presented at Fall meeting of the American Geophysical Union, 2022.

O. A. Pardo (presenter), W. R. Palfey, V. V. Dobrosavljevic, W. Sturhahn, Z. Liu, G. R. Rossman, T. S. Toellner, J. M. Jackson (2022, December) High pressure vibrational properties of szomolnokite. Presented at Fall meeting of the American Geophysical Union, 2022.

W. R. Palfey, W. A. Goddard III, G. R. Rossman (2021, December) Hidden hydrogen – a study of oxygen-substituting hydrogen defects in rutile. Presented at Fall meeting of the American Geophysical Union, 2021.

TEACHING 

Teaching Assistant for Mineralogy (October – December 2019, 2020, 2021): Led the lab section of the course and graded lab reports and homework assignments. Topics covered included: mineral identification, crystallography, point groups, mineral structures, crystal chemistry, mineral spectroscopy, among others. Adapted the course material for remote instruction during the 2020 term. 

Teaching Assistant for Analytical Techniques Laboratory (January – April 2018): Assisted students with instrument use in practical laboratory exercises and graded lab reports. Techniques included: scanning electron microscopy, electron probe microanalysis, laser ablation ICP-MS, Raman spectroscopy, infrared spectroscopy, X-ray fluorescence and powder X-ray diffraction. 

AWARDS 

Best Student Oral Presentation, European Mineralogical Conference - 2024

Richard H. Jahns Teaching Award (Caltech) - 2020 

Virginia Tech Department of Geosciences Outstanding Senior Award - 2017 

Thomas T. Jeffries Geoscience Excellence Award (Virginia Tech) - 2014 

PROFESSIONAL AFFILIATIONS 

Member of Mineralogical Society of America (2021 - present) 

Member of American Geophysical Union (2017 - present) 

SKILLS 

Strong presentation, communication, and teaching skills

Hands on experience modifying and building laboratory equipment and instrumentation

Computational:

Experienced user of: Linux, vim, cluster computing techniques, and VASP (density functional theory)

Analytical:

Extensive knowledge and use of: Fourier transform infrared spectroscopy, Raman spectroscopy, UV-vis spectroscopy, H microanalysis via continuous flow mass spectrometry, X-ray fluorescence (XRF) spectroscopy

Proficient use of: Electron probe microanalysis, single crystal X-ray diffraction

Familiarity with: Solid state 1H nuclear magnetic resonance spectroscopy, electron paramagnetic resonance spectroscopy