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Description
Transition metal oxides are used for numerous applications, includingsemiconductors, batteries, solar cells, catalysis, magnetic devices, and are commonly observed in interstellar media. However, the atomic-scale properties which dictate the overall bulk material activity is still lacking fundamental details. Most importantly, how the electron shells of metals and O atoms mix is inherently significant

Transition metal oxides are used for numerous applications, includingsemiconductors, batteries, solar cells, catalysis, magnetic devices, and are commonly observed in interstellar media. However, the atomic-scale properties which dictate the overall bulk material activity is still lacking fundamental details. Most importantly, how the electron shells of metals and O atoms mix is inherently significant to reactivity. This thesis compares the binding and excited state properties of highly correlated first-row transition metal oxides using four separate transition metal systems of Ti, Cr, Fe and Ni. Laser ablation coupled with femtosecond pump-probe spectroscopy is utilized to resolve the time-dependent excited state relaxation dynamics of atomically precise neutral clusters following 400 nm (3.1 eV) photoexcitation. All transition metal oxides form unique stable stoichiometries with excited state dynamics that evolve due to oxidation, size, or geometry. Theoretical calculations assist in experimental analysis, showing correlations between charge transfer characteristics, electron and hole localization, and magnetic properties to the experimentally determined excited state lifetimes. This thesis finds that neutral Ti and Cr form stable stoichiometries of MO2 (M = Ti, Cr) which easily lose up to two O atoms, while neutral Fe and Ni primarily form MO (M = Fe, Ni) geometries with suboxides also produced. TiO2 clusters possess excited state lifetimes that increase with additional cluster units to ~600 fs, owing to a larger delocalization of excited charge carriers with cluster size. CrO2 clusters show a unique inversed metallic behavior with O content, where the fast (~30 fs) metallic relaxation component associated with electron scattering increases with higher O content, connected to the percent of ligand-to-metal charge transfer (LMCT) character and higher density of states. FeO clusters show a decreased lifetime with size, reaching a plateau of ~150 fs at the size of (FeO)5 related to the density of states as clusters form 3D geometries. Finally, neutral (NiO)n clusters all have similar fast lifetimes (~110 fs), with suboxides possessing unexpected electronic transitions involving s-orbitals, increasing excited state lifetimes up to 80% and causing long-lived states lasting over 2.5 ps. Similarities are drawn between each cluster system, providing valuable information about each metal oxide species and the evolution of excited state dynamics as a result of the occupied d-shell. The work presented within this thesis will lead to novel materials of increased reactivity while facilitating a deeper fundamental understanding on the effect of electron interactions on chemical properties.
ContributorsGarcia, Jacob M. (Author) / Sayres, Scott G (Thesis advisor) / Yarger, Jeffery (Committee member) / Steimle, Timothy (Committee member) / Arizona State University (Publisher)
Created2021
Description
“Tell It to the Frogs: Fukushima’s nuclear disaster and its impact on the Japanese Tree Frog” is a representation of the work from Giraudeau et. al’s “Carotenoid distribution in wild Japanese tree frogs (Hyla japonica) exposed to ionizing radiation in Fukushima.” This paper looked to see if carotenoid levels in

“Tell It to the Frogs: Fukushima’s nuclear disaster and its impact on the Japanese Tree Frog” is a representation of the work from Giraudeau et. al’s “Carotenoid distribution in wild Japanese tree frogs (Hyla japonica) exposed to ionizing radiation in Fukushima.” This paper looked to see if carotenoid levels in the tree frog’s vocal sac, liver, and blood were affected by radiation from Fukushima’s power plant explosion. Without carotenoids, the pigment that gives the frogs their orange color on their necks, their courtship practices would be impacted and would not be as able to show off their fitness to potential mates. The artwork inspired by this research displayed the tree frog’s degradation over time due to radiation, starting with normal life and ending with their death and open on the table. The sculptures also pinpoint where the carotenoids were being measured with a brilliant orange glaze. Through ceramic hand building, the artist created larger than life frogs in hopes to elicit curiosity about them and their plight. While the paper did not conclude any changes in the frog’s physiology after 18 months of exposure, there are still questions that are left unanswered. Why did these frogs not have any reaction? Could there be any effects after more time has passed? Is radiation leakage as big of a problem as previously thought? The only way to get the answers to these questions is to be aware of these amphibians, the circumstances that led them to be involved, and continued research on them and radiation.
ContributorsWesterfield, Savannah (Author) / Beiner, Susan (Thesis director) / McGraw, Kevin (Committee member) / School of Life Sciences (Contributor) / School of Art (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
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Description
Experimentation with glaze materials resulted in 2 functional and interesting base glazes with multiple color variants each. A semi-matte stoneware glaze was created, however after being unable to replicate a specific coloring without drying out the glaze, it was discovered that using this glaze to spray over specific studio glazes

Experimentation with glaze materials resulted in 2 functional and interesting base glazes with multiple color variants each. A semi-matte stoneware glaze was created, however after being unable to replicate a specific coloring without drying out the glaze, it was discovered that using this glaze to spray over specific studio glazes produced a more pleasant color effect than the glaze by itself. A glossy clear glaze was created. The glaze crazed minimally, and color variants were created with the rare earth metals erbium, praseodymium, and neodymium, resulting in celadon-like glazes that were pink, green, and bluish purple respectively. Finally, A semi-matte stoneware glaze with high spodumene content was created with two specific color variations
ContributorsVilen, Zachary Kwochka (Author) / Beiner, Susan (Thesis director) / Steimle, Timothy (Committee member) / School of Life Sciences (Contributor) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05