The following are spotlights of recent faculty research publications and lab research projects. To learn more about each of the faculty, please visit their faculty profile pages.
Professor Tessa Calhoun was published in Nano Letters for research titled “Energetics at the Surface: Direct Optical Mapping of Core and Surface Electronic Structure in CdSe Quantum Dots using Broadband Electronic Sum Frequency Generation Microspectroscopy.” In addition to Calhoun, other team members were Brianna Watson, the lead author, and Benjamin Doughty, a staff scientist in the Chemical Sciences Division at ORNL. Brianna was a graduate student in the UT Department of Chemistry and is now conducting postdoctoral research using microscopy at Boston Children’s Hospital. Their electronic sum frequency generation microspectroscopy technique simultaneously mixes different colors of ultrashort laser pulses to generate new colors of light that describe these elusive ‘dark stats’ on the quantum dots. “I was excited by just how many energy levels we could detect with a single measurement at ambient conditions,” Calhoun said. “While many other experiments had suggested the presence of one or more of these states, we are the first to be able to directly show that there is more than one surface state in these quantum dots.” Knowing more about these surface states will allow scientists to design better nanoparticles and Calhoun’s group is excited for the future systems they can explore with their new microspectroscopy.
The Dai group has published a paper titled “Taming the stability of Pd active phases through a compartmentalizing strategy toward nanostructured catalyst supports” in Nature Communications. This paper reported a new strategy in developing stable supports for high-temperature heterogeneous catalysis. A highly stable catalyst for methane oxidation was successfully developed based on this strategy. The general strategy can be used to synthesize other support architectures for other high-temperature catalysis processes.
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The Dai lab published an article in ChemSusChem and was featured on the front cover of the journal. Bishnu Thapaliya, graduate research assistant, said, “In this work, we demonstrated that direct fluorination of Mxene results a hybrid metal-carbon oxyfluoride with enhanced electrochemical performance compared to traditional oxyfluoride. Therefore, we believe this novel approach opens a new avenue for the development of many 2D hybrid metal-carbon oxyfluoride materials that can be applied to broader materials research.”
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The Journal of the American Chemical Society (JACS) published the Jenkins group’s work “Elucidating the Growth of Metal–Organic Nanotubes Combining Isoreticular Synthesis with Liquid-Cell Transmission Electron Microscopy.” Kristina Vailonis, graduate student in the Jenkins lab, said “Our goal is to observe the formation of a single nanotube or small bundle of nanotubes before the bulk phase is formed. We achieved this goal through rational ligand design by the Jenkins group at The University of Tennessee and the use of in situ liquid-cell transmission electron microscopy (LCTEM) by our collaborators Dr. Nathan Gianneschi and Dr. Karthikeyan Gnanasekaran at Northwestern University.”
Professor David Jenkins and coworkers published a communication demonstrating the first five‑coordinate imide complexes on iron in Angewandte Chemie International Edition. An imide is a nitrogen-metal multiple bond ligand that is associated with catalytic oxidation reactions where a nitrene (NR group) is transferred to an organic substrate. Jenkins is interested in iron imides due to his studies on aziridination. Jenkins said, “An aziridine is a three-membered ring with two carbon atoms and one nitrogen atom that are useful in pharmaceutical syntheses. These five‑coordinate iron imides are postulated to be key intermediates in catalytic aziridination so their isolation may lend insight into this catalytic reaction.” Notably in this study, changing the carbon group bound to the nitrogen changed the spin state at the iron center. Thus, these metal complexes required careful structural characterization at the department’s new X-ray facility, spectroscopic measurements (at UT and Harvard University), and theoretical calculations by Prof. Vogiatzis.
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The Vogiatzis group’s recent work “Data-Driven Acceleration of the Coupled-Cluster Singles and Doubles Iterative Solver” was published in the Journal of Physical Chemistry Letters. Machine learning has changed our lives through improved speech recognition, automated vehicle operation, optimized web searching and recommendation, and beyond. Jacob Townsend, graduate student in the Vogiatzis lab, said, “Our goal is to take this technology, and allow our calculations to learn from previously executed calculations without introducing any approximations or alchemical approaches. Therefore, the desirable accuracy is reached with significantly less computational effort.”
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The Xue group had their paper “Probing Magnetic Excitations in CoII Single‐Molecule Magnets by Inelastic Neutron Scattering” published and was selected as the front cover art in the European Journal of Inorganic Chemistry. This research explores how single-molecule magnets (SMMs) and qubits are of intense current interest for their potential applications as new generation of data storage materials and quantum computing. Graduate student, Duncan Moseley, said, “The cobalt compound studied here shows SMM properties. Direct observation of magnetic transitions in SMMs and spectroscopic characterization of phonons (molecular and lattice vibrations) in SMMs are challenging.”
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