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Full-Text Articles in Physics
Electronic Structure And Stability Of Ligated Superatoms And Bimetallic Clusters, William H. Blades
Electronic Structure And Stability Of Ligated Superatoms And Bimetallic Clusters, William H. Blades
Theses and Dissertations
Quantum confinement in small metal clusters leads to a bunching of states into electronic shells reminiscent of shells in atoms. The addition of ligands can tune the valence electron count and electron distribution in metal clusters. A combined experimental and theoretical study of the reactivity of methanol with AlnIm− clusters reveals that ligands can enhance the stability of clusters. In some cases the electronegative ligand may perturb the charge density of the metallic core generating active sites that can lead to the etching of the cluster. Also, an investigation is conducted to understand how the bonding …
Inducing Active Sites In Clusters: Reactivity Of Al13ix- And Al14iy- (X=0-2, Y=2-4) With Methanol, Christopher Powell
Inducing Active Sites In Clusters: Reactivity Of Al13ix- And Al14iy- (X=0-2, Y=2-4) With Methanol, Christopher Powell
Theses and Dissertations
Size selective reactivity has been observed in pure aluminum cluster anions as a result of Lewis acid and base pairs. Using this a starting point, the goal of this study has been to explore how reactivity is affected with the addition of one or more ligand, which may induce active sites on the surface of the metal clusters. To study this, a theoretical investigation was undertaken on Al13Ix- and Al14Iy- (x=0-2, y=2-4) and their reactivity with methanol. The hypothesis was that iodine can induce a Lewis base site on the opposite side of the cluster, which may enhance reactivity. In …
Stm Studies Of Oxygen Etching Of Silicon Surfaces, Mary L. Willis
Stm Studies Of Oxygen Etching Of Silicon Surfaces, Mary L. Willis
Theses and Dissertations
This study uses atomic force microscopy (AFM) to investigate the oxygen etching behavior of the following silicon surface orientations: (001), (111), (113), (5 5 12) and (112). Most etching was performed at sample temperatures between 650 °C and 800 °C, at pressures of 3.3×10-7 and 1.5×10-7 Torr, and at an exposure of 200 L. Surface orientation strongly influences the morphology resulting from extended etching. The surface orientations that are stable against etching and remain flat include Si(001), Si(111), and Si(113). Such surfaces also include island structures, which result from etching around oxide-induced pinning sites. The density of these islands increases …