Joseph A. Fournier
University of Chicago
Hydrogen bondAnalytical chemistryCluster (physics)IonInfrared spectroscopyChemical physicsMass spectrometryInorganic chemistryAtomic physicsChemistryConformational isomerismIonic bondingRotational spectroscopySpectroscopyMoleculeMolecular physicsNuclear magnetic resonanceSpectral lineProtonPhotochemistryCrystallographyReaction rate constant
52Publications
22H-index
987Citations
Publications 52
Newest
#1Liangyi Chen (WashU: Washington University in St. Louis)
#2Jessika L. S. Dean (WashU: Washington University in St. Louis)
Last. Joseph A. Fournier (WashU: Washington University in St. Louis)H-Index: 22
view all 3 authors...
Herein, we present the initial steps toward developing a framework that will enable the characterization of photoinitiated dynamics within large molecular ions in the gas phase with temporal and energy resolution. We combine the established techniques of tag-loss action spectroscopy on cryogenically trapped molecular ions with ultrafast vibrational spectroscopy by measuring the linear action spectrum of N2-tagged protonated diglycine (GlyGlyH+·N2) with an ultrafast infrared (IR) pulse pair. The ...
Source
#1Liangyi Chen (WashU: Washington University in St. Louis)
#2Joseph A. Fournier (WashU: Washington University in St. Louis)H-Index: 22
Hydrogen-bonding interactions within a series of phenol-benzimidazole model proton-coupled electron transfer (PCET) dyad complexes are characterized using cryogenic ion vibrational spectroscopy. A highly red-shifted and surprisingly broad (>1000 cm-1) transition is observed in one of the models and assigned to the phenolic OH stretch strongly H-bonded to the N(3) benzimidazole atom. The breadth is attributed to a combination of anharmonic Fermi-resonance coupling between the OH stretch and backg...
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#1William B. Carpenter (U of C: University of Chicago)H-Index: 10
#2Nick Lewis (U of C: University of Chicago)H-Index: 25
Last. Andrei Tokmakoff (U of C: University of Chicago)H-Index: 73
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Aqueous proton transport is uniquely rapid among aqueous processes, mediated by fluctuating hydrogen bond reorganization in liquid water. In a process known as Grotthuss diffusion, the excess charge diffuses primarily by sequential proton transfers between water molecules rather than standard Brownian motion, which explains the anomalously high electrical conductivity of acidic solutions. Employing ultrafast IR spectroscopy, we use the orientational anisotropy decay of the bending vibrations of ...
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#1Nick Lewis (U of C: University of Chicago)H-Index: 25
#2Joseph A. Fournier (WashU: Washington University in St. Louis)H-Index: 22
Last. Andrei Tokmakoff (U of C: University of Chicago)H-Index: 73
view all 4 authors...
Ion–ion interactions and ion pairing play an important role in the properties of concentrated electrolyte solutions, yet remain difficult to study due to the heterogeneous and highly dynamic behavior of these systems. In concentrated acid solutions, these questions take on a further level of complexity because the structure of the aqueous proton itself is uncertain and may be influenced by the counterion. Here, we address these questions by studying the IR spectra of nitric acid as a function of...
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#1Joseph A. Fournier (U of C: University of Chicago)H-Index: 22
#2William B. Carpenter (U of C: University of Chicago)H-Index: 10
Last. Andrei Tokmakoff (U of C: University of Chicago)H-Index: 73
view all 4 authors...
Given the critical role of the aqueous excess proton in redox chemistry, determining its structure and the mechanism of its transport in water are intense areas of experimental and theoretical research. The ultrafast dynamics of the proton’s hydration structure has made it extremely challenging to study experimentally. Using ultrafast broadband two-dimensional infrared spectroscopy, we show that the vibrational spectrum of the aqueous proton is fully consistent with a protonated water complex br...
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#1William B. Carpenter (U of C: University of Chicago)H-Index: 10
#2Joseph A. Fournier (U of C: University of Chicago)H-Index: 22
Last. Andrei Tokmakoff (U of C: University of Chicago)H-Index: 73
view all 4 authors...
Aqueous proton transport involves the ultrafast interconversion of hydrated proton species that are closely linked to the hydrogen bond dynamics of water, which has been a long-standing challenge to experiments. In this study, we use ultrafast IR spectroscopy to investigate the distinct vibrational transition centered at 1750 cm–1 in strong acid solutions, which arises from bending vibrations of the hydrated proton complex. Broadband ultrafast two-dimensional IR spectroscopy and transient absorp...
Source
#1William B. Carpenter (U of C: University of Chicago)H-Index: 10
#2Joseph A. Fournier (U of C: University of Chicago)H-Index: 22
Last. Andrei Tokmakoff (U of C: University of Chicago)H-Index: 73
view all 5 authors...
Liquid water's rich sub-picosecond vibrational dynamics arise from the interplay of different high and low-frequency modes evolving in a strong yet fluctuating hydrogen bond network. Recent studies of the OH stretching excitations of H2O indicate that they are delocalized over several molecules, raising questions about whether the bending vibrations are similarly delocalized. In this paper, we take advantage of an improved 50 fs time-resolution and broadband infrared (IR) spectroscopy to interro...
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#1Rajib Biswas (U of C: University of Chicago)H-Index: 13
#2William B. Carpenter (U of C: University of Chicago)H-Index: 10
Last. Andrei Tokmakoff (U of C: University of Chicago)H-Index: 73
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The local environmental sensitivity of infrared (IR) spectroscopy to a hydrogen-bonding structure makes it a powerful tool for investigating the structure and dynamics of excess protons in water. Although of significant interest, the line broadening that results from the ultrafast evolution of different solvated proton-water structures makes the assignment of liquid-phase IR spectra a challenging task. In this work, we apply a normal mode analysis using density functional theory of thousands of ...
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#1Conrad T. Wolke (Yale University)H-Index: 12
#2Joseph A. Fournier (Yale University)H-Index: 22
Last. Mark A. Johnson (Yale University)H-Index: 78
view all 10 authors...
The Grotthuss mechanism explains the anomalously high proton mobility in water as a sequence of proton transfers along a hydrogen-bonded (H-bonded) network. However, the vibrational spectroscopic signatures of this process are masked by the diffuse nature of the key bands in bulk water. Here we report how the much simpler vibrational spectra of cold, composition-selected heavy water clusters, D+(D2O)n, can be exploited to capture clear markers that encode the collective reaction coordinate along...
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#1Luigi De Marco (U of C: University of Chicago)H-Index: 15
#2Joseph A. Fournier (U of C: University of Chicago)H-Index: 22
Last. Andrei Tokmakoff (U of C: University of Chicago)H-Index: 73
view all 5 authors...
Water’s extended hydrogen-bond network results in rich and complex dynamics on the sub-picosecond time scale. In this paper, we present a comprehensive analysis of the two-dimensional infrared (2D IR) spectrum of O–H stretching vibrations in liquid H2O and their interactions with bending and intermolecular vibrations. By exploring the dependence of the spectrum on waiting time, temperature, and laser polarization, we refine our molecular picture of water’s complex ultrafast dynamics. The spectra...
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