Background:
- President's Postdoctoral Fellow, University of California, Los Angeles
- Army Research Office Young Investigator Program Award
- NSF CAREER Award
Research in the CC Jarrold group involves the application of mass spectrometry, anion photoelectron spectroscopy and density functional theory calculations to a wide range of chemically interesting systems. Several ongoing projects include the following.
1. Heterogeneous catalysts
(a) Alumina is a very common material used as a catalytic support as well as a catalyst. Determining how small, displaced fragments of this material interact with water will tell us how alumina is actually contributing to the activity in supported metal catalysts. (b) Improving the environment by optimizing hydrodesulfurization of petrochemicals with transition metal chalcogenides.
2. Tandem photoelectrochemical cells for the solar energy-driven cleavage of water
We probe how water interacts with the ground and photoexcited states of molybdenum oxide and titanium oxide clusters in order to predict the best design for these cells that may be used to generate H2 fuel.
3. Measuring the dipole moment of -helices
The dipole moment of -helices can be tens of debye, and this dipole moment may play a role in protein folding, steering a substrate into its correct conformation within the protein, electronic activation of the substrate, or ion gate operation. However, gas-phase determination of the dipole moment in various helices has so far been elusive.
All of these projects start with negative ions. Initiating studies with anions has numerous advantages. First, these systems are inherently mass selectable, thereby eliminating any ambiguity regarding species identification. Second, depending on the system, the anions' "excess" electron is generally located in places that are sensitive to how the constituent atoms are bound, or even the dipole moment of the resulting neutral. So by detaching the electron from the anion, we learn about the properties of the associated neutral. And the density functional theory calculations provide an invaluable tool for the analysis of the spectra of complicated systems. Using this combination of tools, we extract detailed information regarding the structure, chemical and electronic properties of this broad range of systems.
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This puckered D2d structure is consistent with the observed photoelectron spectrum of Al5O4-, a hypermetallic cluster. The calculations on the water complexes indicate that water adds by first approaching the most electron-deficient Al-atom, then by dissociating and transferring a proton to one of the equivalent O-atoms. |
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Selected Publications:
"Reactivity of Al3O3 toward H2O studied by density functional theory," F. Ahu Akin and Caroline C. Jarrold, Journal of Chemical Physics, 120, 8690 (2004).
"A comparison of stable carbonyls formed in the gas phase reaction between group 10 atomic anions and methanol or methoxy radicals: Anion photoelectron spectroscopy and density functional theory calculations on HNiCO, PdCO, and PtCO," Bappaditya Chatterjee, F. Ahu Akin, Caroline Chick Jarrold and Krishnan Raghavachari, Journal of Chemical Physics, 119, 10591 (2003).
"Addition of water and methanol to Al3O3- studied by mass spectrometry and anion photoelectron spectroscopy," F. Ahu Akin and Caroline Chick Jarrold, Journal of Chemical Physics, 118, 5841 (2003).
"Separating contributions from multiple structural isomers in anion photoelectron spectra: Al3O3- beam hole burning," F. Ahu Akin and Caroline Chick Jarrold, Journal of Chemical Physics, 118, 1773 (2003).
"Comparison of CaF, ZnF, CaO, and ZnO: Their anions and cations in their ground and low-lying excited states," James F. Harrison, Robert W. Field and Caroline Chick Jarrold, ACS Symposium Series, 828, 238 (2002).
