Joseph S Francisco

Purdue University, West Lafayette, Indiana, United States

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Publications (414)1502.57 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The hydrolysis of ketene (H2C=C=O) to form acetic acid involving two water molecules and also separately in the presence of one to two water molecules plus formic acid (FA) has been investigated. Our results show that while the currently accepted indirect mechanism, involving addition of water across the carbonyl C=O bond of ketene to form an ene-diol followed by tautomerization of the ene-diol to form acetic acid is the preferred pathway when water alone is present, with formic acid as catalyst, addition of water across the ketene C=C double bond to directly produce acetic acid, becomes the kinetically favored pathway for temperatures below 400K.We find that the overall barrier for ketene hydrolysis involving one water molecule plus formic acid (H2C2O + H2O + FA) is not only significantly lower than that involving two water molecules (H2C2O + 2H2O), but that FA is able to reduce the barrier height for the direct path, involving addition of water across the C=C double bond, so that it is essentially identical with(6.4 kcal/mol) that for the indirect ene-diol formation path involving addition of water across the C=O bond. For the case of ketene hydrolysis involving two water molecules plus formic acid (H2C2O + 2H2O + FA), the barrier for the direct addition of water across the C=C double bond is reduced even further, and is 2.5 kcal/mol lower relative to the ene-diol path involving addition of water across the C=O bond. In fact, the hydrolysis barrier for the H2C2O + 2H2O + FA reaction through the direct path is sufficiently low (2.5 kcal/mol) for it to be an energetically accessible pathway for acetic acid formation under atmospheric conditions. Given the structural similarity between acetic and formic acid, our results also have potential implications for aqueous phase chemistry. Thus in an aqueous environment, even in the absence of formic acid, though the initial mechanism for ketene hydrolysis is expected to involve addition of water across the carbonyl bond as is currently accepted, the production and accumulation of acetic acid will likely alter the preferred pathway to one involving addition of water across the ketene C=C double bond as the reaction proceeds.
    The journal of physical chemistry. A. 01/2015;
  • Lei Tan, Frantisek Turecek, Joseph S Francisco, Yu Xia
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    ABSTRACT: Heteroatom-centered radicals are known to play critical roles in atmospheric chemistry, organic synthesis, and biology. While most studies have focused on the radical reactivity such as hydrogen abstraction, the base properties of heteroatom-centered radicals have long been overlooked, despite the profound consequences, such as their ability to participate in hydrogen-bonding networks. In this study, we use the sulfinyl radical (-SO•) as a model to show that the dual properties of heteroatom-centered radicals, i.e., their ability to function as a radical and a base, can coexist in peptides and be differentiated by examining the loss of hydrosulfinyl radical (SOH) upon unimolecular dissociation of the peptide sulfinyl radical ions in the gas phase. The loss of SOH can result from two channels: one involves hydrogen atom abstraction, which reflects the radical property; the other is initiated by proton transfer to the sulfinyl radical, manifesting its base property. Tuning of the two properties of peptide sulfinyl radicals can be achieved by varying the chemical properties of the neighboring functional groups, which demonstrates the influence of the local chemical environment on the behavior of the radical species. The experimental approach established in this study to probe the dual chemical property of peptide sulfinyl radical can be potentially applied to studying other types of heteroatom-centered radical species of biological significance.
    The Journal of Physical Chemistry A 11/2014; · 2.78 Impact Factor
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    ABSTRACT: Post-translational mechanisms of protein oxidation as a result of reactive oxygen species (ROS) can occur under physiological conditions to yield selective side-chain and backbone modifications including abstractions, donations, additions, substitutions, and fragmentation. In order to characterize the selectivity of radical-mediated fragmentation, quantum mechanical investigations using ab initio and density functional methods were employed to evaluate site, conformation, and pathway trends of small trialanine peptides resembling a β-strand and a β-turn. Comparisons of reaction enthalpies show that the diamide pathway is more energetically favorable than the α-amidation pathway and that both pathways are site and conformationally selective. These findings readily contribute to the understanding of oxidative stress in biochemical processes.
    The Journal of Physical Chemistry A 11/2014; · 2.78 Impact Factor
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    ABSTRACT: The present theoretical calculations on CP X2Σ+, A2Π, 14Σ+, 14Δ, 14Π, 16Π and 16Σ+ electronic states use standard and explicitly correlated coupled cluster approaches, multi-reference configuration interaction (MRCI) techniques in connection with a large panel of basis sets. We also examined core–valence (CV) and scalar relativistic (SR) effects. For the ground electronic state, our calculations reveal that the MRCI+CV+SR method and the coupled cluster technique with perturbative treatment of triple excitations including scalar relativistic effects computed with the Douglas-Kroll approach (RCCSD[T]-DK) in connection with a large basis set lead to an accurate description of CP(X2Σ+). We computed the evolution along the internuclear distance of the diagonal and the off-diagonal spin–orbit integrals between the X2Σ+ and A2Π states. These integrals are then incorporated together with the corresponding potentials into variational treatment of the nuclear motion. We deduced hence the energy positions of the low and high vibronic levels of X2Σ+ and A2Π states. Finally, it is shown the necessity of considering the spin–orbit coupling for accurate prediction of the energy position of these levels.
    Molecular Physics 10/2014; 112(20). · 1.64 Impact Factor
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    ABSTRACT: One route to break down halomethanes is through reactions with radical species. The capability of the artificial force-induced reaction algorithm to efficiently explore a large number of radical reaction pathways has been illustrated for reactions between haloalkanes (CX3Y; X=H, F; Y=Cl, Br) and ground-state (2Σ+) cyano radicals (CN). For CH3Cl+CN, 71 stationary points in eight different pathways have been located and, in agreement with experiment, the highest rate constant (108 s−1 M−1 at 298 K) is obtained for hydrogen abstraction. For CH3Br, the rate constants for hydrogen and halogen abstraction are similar (109 s−1 M−1), whereas replacing hydrogen with fluorine eliminates the hydrogen-abstraction route and decreases the rate constants for halogen abstraction by 2–3 orders of magnitude. The detailed mapping of stationary points allows accurate calculations of product distributions, and the encouraging rate constants should motivate future studies with other radicals.
    ChemPhysChem 09/2014; · 3.36 Impact Factor
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    ABSTRACT: Equation of motion coupled cluster calculations were performed on various structures of OH in clusters with one, two, three, and four water molecules to determine the energies of valence and charge transfer states. Motivation for these calculations is to understand the absorption spectrum of OH in water. Previous calculations on these species have confirmed that the longer wavelength transition observed is due to the A((2)∑) ← X((2)∏) valence transition, while the shorter wavelength transition is due to a charge-transfer from H2O to OH. While these previous calculations identified the lowest energy charge-transfer state, our calculations have included sufficient states to identify additional solvent-to-solute charge transfer states. The minimum energy structures of the clusters were determined by application of the Monte Carlo technique to identify candidate cluster structures, followed by optimization at the level of second-order Møller-Plesset perturbation theory. Calculations were performed on two structures of OH-H2O, three structures of OH-(H2O)2, four structures of OH-(H2O)3, and seven structures of OH-(H2O)4. Confirming previous calculations, as the number of water molecules increases, the energies of the excited valence and charge-transfer states decrease; however, the total number of charge-transfer states increases with the number of water molecules, suggesting that in the limit of OH in liquid water, the charge-transfer states form a band.
    The Journal of Chemical Physics 09/2014; 141(10):104315. · 3.12 Impact Factor
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    ABSTRACT: First-principles simulations suggest that additional OH formation in the troposphere can result from ozone interactions with the surface of cloud droplets. Ozone exhibits an affinity for the air-water interface, which modifies its UV and visible light spectroscopic signatures and photolytic rate constant in the troposphere. Ozone cross sections on the red side of the Hartley band (290- to 350-nm region) and in the Chappuis band (450-700 nm) are increased due to electronic ozone-water interactions. This effect, combined with the potential contribution of the O3 + hν → O((3)P) + O2(X(3)Σg (-)) photolytic channel at the interface, leads to an enhancement of the OH radical formation rate by four orders of magnitude. This finding suggests that clouds can influence the overall oxidizing capacity of the troposphere on a global scale by stimulating the production of OH radicals through ozone photolysis by UV and visible light at the air-water interface.
    Proceedings of the National Academy of Sciences 07/2014; · 9.81 Impact Factor
  • Mariano Méndez, Joseph S. Francisco, David A. Dixon
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    ABSTRACT: Simple hydrides of compounds containing N, S, and O are of significant interest due to the role that they play in atmospheric chemistry and in biological pathways. There is a lack of quantitative thermodynamic data on these compounds. We have used a reliable computational chemistry approach based on valence CCSD(T) calculations extrapolated to the complete basis set limit with additional corrections to predict the heats of formation and bond dissociation energies of such compounds. The results show that compounds with the ability of the central S atom to effectively expand its valency leads to more stable isomers and, as a consequence, that those with the NSO structural motif are thermochemically more stable than those with the SNO motif. In addition, SO bonds are preferred over NO bonds.
    Chemistry - A European Journal 07/2014; · 5.93 Impact Factor
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    ABSTRACT: Neon hydrate was synthesized and studied by in situ neutron diffraction at 480 MPa and temperatures ranging from 260 to 70 K. For the first time to our knowledge, we demonstrate that neon atoms can be enclathrated in water molecules to form ice II-structured hydrates. The guest Ne atoms occupy the centers of D2O channels and have substantial freedom of movement owing to the lack of direct bonding between guest molecules and host lattices. Molecular dynamics simulation confirms that the resolved structure where Ne dissolved in ice II is thermodynamically stable at 480 MPa and 260 K. The density distributions indicate that the vibration of Ne atoms is mainly in planes perpendicular to D2O channels, whereas their distributions along the channels are further constrained by interactions between adjacent Ne atoms.
    Proceedings of the National Academy of Sciences 07/2014; · 9.81 Impact Factor
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    ABSTRACT: We performed accurate ab initio investigations of the geometric parameters and the vibrational structure of neutral HNS/HSN triatomics and their singly charged anions and cations. We used standard and explicitly correlated coupled cluster approaches in connection with large basis sets. At the highest levels of description, we show that results nicely approach those obtained at the complete basis set limit. Moreover, we generated the three-dimensional potential energy surfaces (3D PESs) for these molecular entities at the coupled cluster level with singles and doubles and a perturbative treatment of triple excitations, along with a basis set of augmented quintuple-zeta quality (aug-cc-pV5Z). A full set of spectroscopic constants are deduced from these potentials by applying perturbation theory. In addition, these 3D PESs are incorporated into variational treatment of the nuclear motions. The pattern of the lowest vibrational levels and corresponding wavefunctions, up to around 4000 cm(-1) above the corresponding potential energy minimum, is presented for the first time.
    The Journal of Chemical Physics 06/2014; 140(24):244309. · 3.12 Impact Factor
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    ABSTRACT: Carbon monoxide clathrate hydrate is a potentially important constituent in the solar system. In contrast to the well-established relation between the size of gaseous molecule and hydrate structure, previous work showed that carbon monoxide molecules preferentially form structure-I rather than structure-II gas hydrate. Resolving this discrepancy is fundamentally important to understanding clathrate formation, structure stabilization and the role the dipole moment/molecular polarizability plays in these processes. Here we report the synthesis of structure-II carbon monoxide hydrate under moderate high-pressure/low-temperature conditions. We demonstrate that the relative stability between structure-I and structure-II hydrates is primarily determined by kinetically controlled cage filling and associated binding energies. Within hexakaidecahedral cage, molecular dynamic simulations of density distributions reveal eight low-energy wells forming a cubic geometry in favour of the occupancy of carbon monoxide molecules, suggesting that the carbon monoxide-water and carbon monoxide-carbon monoxide interactions with adjacent cages provide a significant source of stability for the structure-II clathrate framework.
    Nature Communications 06/2014; 5:4128. · 10.74 Impact Factor
  • Montu K Hazra, Joseph S Francisco, Amitabha Sinha
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    ABSTRACT: The hydrolysis of glyoxal involving one to three water molecules and also in the presence of a water molecule and formic acid has been investigated. Our results show that glyoxal-diol is the major product of the hydrolysis and that formic acid, through its ability to facilitate intermolecular hydrogen atom transfer, is considerably more efficient compared to water as a catalyst in the hydrolysis process. Additionally once the glyoxal-diol is formed, the barrier for further hydrolysis to form the glyoxal-tetrol is effectively reduced to zero in the presence of a single water and formic acid molecule. There are two important implications arising from these findings. First, the results suggest that under the catalytic influence of formic acid, glyoxal hydrolysis can impact the growth of atmospheric aerosols. As a result of enhanced hydrogen bonding, mediated through their polar OH functional groups, the diol and tetrol products are expected to have significantly lower vapor pressure compared to the parent glyoxal molecule; hence they can more readily partition into the particle phase and contribute to the growth of secondary organic aerosols. In addition, our findings provide insight into how glyoxal-diol and glyoxal-tetrol might be formed under atmospheric conditions associated with water restricted environments and strongly suggest that the formation of these precursors for secondary organic aerosol growth is not likely restricted solely to the bulk aqueous phase as is currently assumed.
    The Journal of Physical Chemistry A 05/2014; · 2.77 Impact Factor
  • Lei Tan, Hanfeng Hu, Joseph S. Francisco, Yu Xia
    Angewandte Chemie 02/2014; 126(7):1739-1739.
  • Lei Tan, Hanfeng Hu, Joseph S Francisco, Yu Xia
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    ABSTRACT: Glycyl radicals are important bioorganic radical species involved in enzymatic catalysis. Herein, we demonstrate that the stability of glycyl-type radicals (X-(.) CH-Y) can be tuned on a molecular level by varying the X and Y substituents and experimentally probed by mass spectrometry. This approach is based on the gas-phase dissociation of cysteine sulfinyl radical (X-Cys SO .-Y) ions through homolysis of a Cα Cβ bond. This fragmentation produces a glycyl-type radical upon losing CH2 SO, and the degree of this loss is closely tied to the stability of the as-formed radical. Theoretical calculations indicate that the energy of the Cα Cβ bond homolysis is predominantly affected by the stability of the glycyl radical product through the captodative effect, rather than that of the parent sulfinyl radical. This finding suggests a novel experimental method to probe the stability of bioorganic radicals, which can potentially broaden our understanding of these important reactive intermediates.
    Angewandte Chemie International Edition 01/2014; · 11.34 Impact Factor
  • Kirk A. Peterson, Joseph S. Francisco
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    ABSTRACT: A systematic ab initio treatment of the nitryl halides (XNO2) and the cis- and trans- conformers of the halide nitrites (XONO), where X = Cl, Br, and I, have been carried out using highly correlated methods with sequences of correlation consistent basis sets. Equilibrium geometries and harmonic frequencies have been accurately calculated in all cases at the explicitly correlated CCSD(T)-F12b level of theory, including the effects of core-valence correlation for the former. Where experimental values are available for the equilibrium structures (ClNO2 and BrNO2), the present calculations are in excellent agreement; however, the X-O distances are slightly too long by about 0.01 Å due to missing multireference effects. Accurate predictions for the iodine species are made for the first time. The vertical electronic excitation spectra have been calculated using equation-of-motion coupled cluster methods for the low-lying singlet states and multireference configuration interaction for both singlet and triplet states. The latter also included the effects of spin-orbit coupling to provide oscillator strengths for the ground state singlet to excited triplet transitions. While for ClNO2 the transitions to excited singlet states all occur at wavelengths shorter than 310 nm, there is one longer wavelength singlet transition in BrNO2 and two in the case of INO2. The long wavelength tail in the XNO2 species is predicted to be dominated by transitions to triplet states. In addition to red-shifting from X = Cl to I, the triplet transitions also increase in oscillator strength, becoming comparable to many of the singlet transitions in the case of INO2. Hence in particular, the latter species should be very photolabile. Similar trends are observed and reported for the halogen nitrites, many of which for the first time.
    The Journal of Chemical Physics 12/2013; 140(4). · 3.12 Impact Factor
  • Majdi Hochlaf, Roberto Linguerri, Joseph S Francisco
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    ABSTRACT: Using state-of-the-art theoretical methods, we investigate the lowest electronic states of singlet and triplet spin multiplicities of HSNO. These computations are done using configuration interaction ab initio methods and the aug-cc-pV5Z basis set. One-dimensional cuts of the six-dimensional potential energy surfaces of these electronic states along the HS, SN stretches and HSN, SNO bending and torsion coordinates are calculated. Several avoided crossings and conical intersections are found. We computed also radiative lifetimes and spin-orbit couplings of these electronic states. Our work shows that the dynamics on these excited states is very complex, and suggest that multi-step mechanisms will populate the ground state via radiationless processes or lead to predissociation or intramolecular isomerization. For instance, these potentials are used to propose mechanisms for the IR, Vis, and UV light-induced cis-trans interconversions of HSNO and reactivity towards HS + NO and H + SNO products. Our findings are in good agreement with previous experimental studies on the photochemistry of HSNO. The atmospheric implication of HSNO is also discussed.
    The Journal of Chemical Physics 12/2013; 139(23):234304. · 3.12 Impact Factor
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    ABSTRACT: Accurate ab initio computations of structural and spectroscopic parameters for the HPS∕HSP molecules and corresponding cations and anions have been performed. For the electronic structure computations, standard and explicitly correlated coupled cluster techniques in conjunction with large basis sets have been adopted. In particular, we present equilibrium geometries, rotational constants, harmonic vibrational frequencies, adiabatic ionization energies, electron affinities, and, for the neutral species, singlet-triplet relative energies. Besides, the full-dimensional potential energy surfaces (PESs) for HPS(x) and HSP(x) (x = -1,0,1) systems have been generated at the standard coupled cluster level with a basis set of augmented quintuple-zeta quality. By applying perturbation theory to the calculated PESs, an extended set of spectroscopic constants, including τ, first-order centrifugal distortion and anharmonic vibrational constants has been obtained. In addition, the potentials have been used in a variational approach to deduce the whole pattern of vibrational levels up to 4000 cm(-1) above the minima of the corresponding PESs.
    The Journal of Chemical Physics 11/2013; 139(17):174313. · 3.12 Impact Factor
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    ABSTRACT: Ozone-water complexes O3•••(H2O)n (n=1-4) have been theoretically investigated using QCISD and CCSD(T) methods along with the 6-311G(2df,2p), 6-311+G(2df,2p), aug-cc-pVDZ, aug-cc-pVTZ, aug-cc-pVQZ basis sets and extrapolation to CBS limit. For comparison, water clusters (H2O)n (n=1-4) have also been studied at the same level of theory. The ozone-water complexes are held together by a combination of weak specific hydrogen bonding and van der Waals interactions. Surprisingly, the hydrogen-bonded complexes are not necessarily the most stable ones. In particular, in the most stable 1:1 complex structure the main stabilizing factors come from van der Waals interactions. The high accuracy of the calculated binding energies provides a reliable basis to discuss the abundance of these clusters in the atmosphere. We predict concentrations up to 9.24x1015, 3.91x1014, and 2.02x1914 molecules•cm-3 for water dimer, trimer and tetramer, in very hot and humid conditions, and that the concentrations of these clusters would remain significant up to 10 km of altitude in the Earth's atmosphere. The concentration of O3•••H2O is predicted to be between one and two orders of magnitude higher than previous estimation from the literature: up to 5.74x108 molecules•cm-3 in very hot and humid conditions at ground level and up to 1.56x107 molecules•cm-3 at 10 km of altitude of the Earth's atmosphere. The concentrations of the other ozone-water clusters, O3••(H2O)2, O3•••(H2O)3, and O3•••(H2O)4 are predicted to be very small or even negligible in the atmosphere.
    The Journal of Physical Chemistry A 09/2013; · 2.77 Impact Factor
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    ABSTRACT: The existence of the rare six-membered and intramolecular C-H…F-C hydrogen-bond has been experimentally proved in the gas phase and in the solid state recently. However, the effect of the substituents on this C-H…F-C hydrogen-bond system has never been reported. In view of the importance of this type of C-H…F-C H-bonding whose weak interaction has been found critical in nanotechnology and biological systems, the nine functional groups composed of electron donating and electron withdrawing groups are exerted into this C-H…F-C H-bonding system in order to study the group effect on the hydrogen bonding. Group effects on this C-H…F-C H-bonding system have been found, and their effects on the H-bonding system have been quantified and found to be tunable.
    The Journal of Physical Chemistry A 08/2013; · 2.77 Impact Factor
  • C Eric Cotton, Joseph S Francisco, William Klemperer
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    ABSTRACT: This work reports the results of a high level ab initio study of the linear proton bound ion-molecule complex of HCNH(+) with HCN and its isomer HNC. The energetics, equilibrium geometries, and predicted equilibrium rotational constants of three strongly interacting ion-molecule complexes are reported from calculations performed at the coupled-cluster calculations including singles, doubles, and perturbative triple excitations (CCSD(T))∕aug-cc-pVnZ (n = 2-5) level of theory. Harmonic vibrational frequencies from calculations performed at the CCSD(T)∕aug-cc-pVnZ (n = 2-4) level of theory are presented. Additional calculations are performed at the CCSD(T)-F12b∕VnZ-F12 level of theory, and the associated energetics, equilibrium geometries, and equilibrium spectroscopic properties are reported. Anharmonicity is treated with the vibrational configuration interaction method, and the predicted anharmonic vibrational frequencies are reported. The results of these calculations show that of the four possible linear interactions of HCNH(+) with HCN and HNC, there are three strongly interacting proton bound complexes. Further, the study presents results that the fourth possible interaction provides the basis for a novel HNC to HCN isomerization pathway in the interstellar medium.
    The Journal of Chemical Physics 07/2013; 139(1):014304. · 3.12 Impact Factor

Publication Stats

3k Citations
1,502.57 Total Impact Points

Institutions

  • 1994–2014
    • Purdue University
      • • Department of Chemistry
      • • Department of Earth and Atmospheric Sciences
      West Lafayette, Indiana, United States
  • 2013
    • Uppsala University
      • Department of Chemistry - Ångström Laboratory
      Uppsala, Uppsala, Sweden
    • Saha Institute of Nuclear Physics
      • Chemical Sciences Division
      Calcutta, Bengal, India
    • University of Tunis El Manar
      • Department of Physics
      Tunis-Ville, Tūnis, Tunisia
  • 2012–2013
    • Laboratoire de Spectroscopie Atomique Moléculaire et Applications
      Tunis-Ville, Tūnis, Tunisia
    • University of Lorraine
      Nancy, Lorraine, France
    • Max Planck Institute for Chemistry
      Mayence, Rheinland-Pfalz, Germany
    • University of Paris-Est
      • Laboratoire de Modélisation et Simulation Multi-Échelle (MSME) - UMR 8208 CNRS
      Descartes, Centre, France
    • Virginia Polytechnic Institute and State University
      • Department of Chemistry
      Blacksburg, VA, United States
  • 2005–2012
    • Bergische Universität Wuppertal
      • • Department of Chemistry and Biology
      • • Inorganic Chemistry
      Wuppertal, North Rhine-Westphalia, Germany
    • East Carolina University
      • Department of Chemistry
      Greenville, NC, United States
  • 2004–2012
    • University of California, San Diego
      • Department of Chemistry and Biochemistry
      San Diego, CA, United States
    • National University of Cordoba, Argentina
      • Department of Physics-Chemistry
      Córdoba, Provincia de Cordoba, Argentina
  • 2011
    • Spanish National Research Council
      • Departament de Química Biològica i Modelització Molecular
      Madrid, Madrid, Spain
  • 2008–2011
    • Brigham Young University - Provo Main Campus
      • Department of Chemistry and Biochemistry
      Provo, UT, United States
    • University of Pennsylvania
      • Department of Chemistry
      Philadelphia, PA, United States
    • Howard University
      • Department of Chemistry
      Washington, West Virginia, United States
  • 2004–2011
    • Washington State University
      • Department of Chemistry
      Pullman, WA, United States
  • 2010
    • Haverford College
      • Department of Chemistry
      Norristown, Pennsylvania, United States
  • 2008–2009
    • Bielefeld University
      • Theoretische Chemie
      Bielefeld, North Rhine-Westphalia, Germany
  • 2007–2009
    • University of Alabama
      • Department of Chemistry
      Tuscaloosa, AL, United States
    • National Institute of Standards and Technology
      Maryland, United States
    • Universität Siegen
      Siegen, North Rhine-Westphalia, Germany
  • 2004–2009
    • University of Bologna
      • "Giacomo Ciamician" Department of Chemistry CHIM
      Bologna, Emilia-Romagna, Italy
  • 2005–2008
    • Brookhaven National Laboratory
      • Chemistry Department
      New York City, NY, United States
  • 1988–2007
    • Wayne State University
      • Department of Chemistry
      Detroit, MI, United States
  • 2006
    • Jackson State University
      • Department of Chemistry and Biochemistry
      Jackson, MS, United States
  • 1993–2006
    • California Institute of Technology
      • • Arthur Amos Noyes Laboratory of Chemical Physics
      • • Jet Propulsion Laboratory
      Pasadena, CA, United States
  • 2003
    • University of Duisburg-Essen
      • Anorganische Chemie Arbeitsgruppe
      Duisburg, North Rhine-Westphalia, Germany
  • 2002
    • Technische Universität München
      München, Bavaria, Germany
  • 1999
    • Williams College
      • Department of Chemistry
      Williamstown, MA, United States
    • University of Illinois, Urbana-Champaign
      • Department of Atmospheric Sciences
      Urbana, IL, United States
  • 1991–1995
    • University of Bath
      • Department of Chemistry
      Bath, ENG, United Kingdom
  • 1987–1988
    • University of Bristol
      • School of Chemistry
      Bristol, ENG, United Kingdom
  • 1985
    • University of Cambridge
      Cambridge, England, United Kingdom