Joseph A. Fournier

Joseph A. Fournier

Assistant Professor of Chemistry
Postdoctoral Fellow, University of Chicago
PhD, Yale University
BS, University of Connecticut
research interests:
  • Ultrafast spectroscopy
  • Infrared laser spectroscopy
  • Mass spectrometry
  • Cryogenic ion trapping and processing
  • Reaction dynamics and mechanisms of proton-coupled electron transfer processes and small molecule catalysis

contact info:

The Fournier lab combines the sensitivity and selectivity of mass spectrometry with the time resolution of ultrafast spectroscopies to capture and directly interrogate fast chemical reactions with molecular-level detail.

Identification and characterization of transient intermediates is crucial for developing detailed molecular-level knowledge of chemical reaction mechanisms – insight that is required to fully understand important biological processes like photosynthesis, energy storage and transfer, and for the rational development of novel synthetic catalysts. However, key reaction intermediates and their dynamics are often too short-lived or technically challenging to capture and interrogate directly with current methods. Next‑generation methods are required to isolate and probe elusive reaction intermediates and transition‑state species with atomistic detail.

Professor Fournier's research program seeks to develop novel experimental techniques which will allow for the capture and direct interrogation of reaction intermediates by combining the high signal sensitivity of mass spectrometry, the high frequency resolution of gas‑phase ion spectroscopies, and the time resolution of ultrafast spectroscopies in a single experiment. The versatility of mass spectrometric techniques allows for the careful control and manipulation of the chemical environment around the reactive system of interest in a composition-selective manner. The well resolved optical spectra that will be obtained from the isolated and cryogenically cooled (10 K) ensembles will yield unambiguous structural identification, while the time evolution of the spectroscopic transitions with ultrafast resolution will characterize the time-evolving shape of the reactive potential energy surface (PES). This data will provide the basis for clear mechanistic interpretation of how the surrounding chemical environment actively dictates the observed reaction dynamics and underlying shape of the PES.

Specifically, he is interested in studying catalytic processes driven by proton-coupled electron transfer (PCET), which are ubiquitous throughout chemistry and biology. His focus includes two forefront problems where clear mechanistic details are vitally needed: (1) The role of tyrosine and tryptophan in biological PCET, in particular, the nature and dynamics of TyrOH•+ and TrpNH•+ radical cation species which are proposed key intermediates in systems including Photosystem II, ribonucleotide reductase, and cytochrome c oxidase. (2) Capturing intermediates generated during the activation of small molecules by organometallic catalysts, specifically, how solvent waters around the active site and ligand composition in water oxidation catalysts drive the formation of the proposed high-valent metal-oxo intermediate.

Selected Publications

Fournier, J.A.; Carpenter, W.B.; Lewis, N.H.C.; Tokmakoff, A. Structure of the Aqueous Proton Characterized by Ultrafast Broadband Infrared Spectroscopy. Nat. Chem., 2018, 10, 932.

Fournier, J.A.; Carpenter, W.; De Marco, L.; Tokmakoff, A.  The Interplay of Ion Water and Water-Water Interactions within the Hydration Shells of Nitrate and Carbonate Directly Probed with 2D IR Spectroscopy. J. Am. Chem. Soc., 2016, 138, 9634.

Wolke, C.T.; Fournier, J.A.; Dzugan, L.D.; McCoy, A.B.; Odbadrakh, T.T; Jordan, K.D.; Fagiani, M.R.; Knorke, H.; Asmis, K.R.; Johnson, M.A. Spectroscopic Snapshots of the Proton Relay Mechanism is Water. Science, 2016, 354, 1131.

Fournier, J.A.; Wolke, C.T.; Johnson, M.A.; Odbadrakh, T.T; Jordan, K.D.; Kathmann, S.M.; Xantheas, S.S.  Snapshots of Proton Accommodation at a Microscopic Water Surface: Understanding the Vibrational Spectral Signatures of the Charge Defect in Cryogenically Cooled H+(H2O)n=2-28 Clusters. J. Phys. Chem. A, 2015, 119, 9425. (Feature Article, cover art)

Fournier, J.A.; Johnson, C.J.; Wolke, C.T.; Weddle, G.H.; Wolk, A.B.; Johnson, M.A.  Vibrational Spectral Signature of the Proton Defect in the Three‑Dimensional H+(H2O)21 Cluster. Science, 2014, 344, 1009.


2021 NSF CAREER Award 

2016 Arnold O. Beckman Postdoctoral Fellow

2011 National Defense Science and Engineering Graduate Fellowship