PHOTOELECTRON SPECTROSCOPY INVESTIGATION OF BORON AND BORIDE CLUSTERS: THE FOUNDATION OF NEW BORON NANOSTRUCTURES

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Overview

Title
PHOTOELECTRON SPECTROSCOPY INVESTIGATION OF BORON AND BORIDE CLUSTERS: THE FOUNDATION OF NEW BORON NANOSTRUCTURES
Contributors
Li, Weili (creator)
Wang, Lai-Sheng (Director)
Weber, Peter (Reader)
Stratt, Richard (Reader)
Brown University. Chemistry (sponsor)
Doi
10.7301/Z0J38QWF
Copyright Date
2014
Abstract
Chemistry is the science of molecules and materials, as well as their compositions, structures, properties and transformations. The search for new materials with tailored properties is a central theme in chemistry. Atomic clusters, with structures and properties intermediate between individual atoms and bulk solids, have provided fertile ground for the understanding of chemical bonding and for the rational design of novel nano-systems. Photoelectron spectroscopy is the most powerful experimental technique to probe the structures and chemical bonding of size-selected clusters. This dissertation mainly focuses on the studies of boron related clusters using combined photoelectron spectroscopy and quantum chemistry calculations. A world of flat boron (Bn−, n ≤ 20) was previously discovered by the Wang group and its collaborators. The research presented in this thesis shows that the flat boron world expands to n = 24 and continues at the sizes of n = 30, 35, 36 and 40. The B30−, B35−, B36− and B40− clusters feature isolated or adjacent hexagonal vacancies in the all-triangular lattices, providing experimental evidence for the viability of the infinitely large boronsheets, for which we coined the word “borophene”. The first experimental observation of an all-boron fullerene is detailed in this thesis at B40−, which is called borospherene. To search for new boron-based motifs or building blocks for new materials, we proposed an electronic design principle for transition metal centered monocyclic molecular wheels (M©Bnq−). Eight-, nine- and ten-membered molecular wheels are discovered on the basis of the design principle. We have also reported boron-based molecular wires, bipyramid as well as half-sandwiched clusters. These clusters serve as potential ligands or building blocks for nanomaterials. Finally, the photoelectron spectra of uranium oxides and fluorides are presented. Uranium exhibits a strong correlation effect between its 7s2 electrons. These actinide compounds are important as benchmarks for calibrating various relativistic quantum chemistry methods, especially those developed for systems with strong electron correlations.
Keywords
Boron Cluster
ab initio calculations
borophene
borospherene
Photoelectron spectroscopy
Uranium
Notes
Thesis (Ph.D. -- Brown University (2014)
Extent
389, 357 p.

Citation

Li, Weili, "PHOTOELECTRON SPECTROSCOPY INVESTIGATION OF BORON AND BORIDE CLUSTERS: THE FOUNDATION OF NEW BORON NANOSTRUCTURES" (2014). Chemistry Theses and Dissertations. Brown Digital Repository. Brown University Library. https://doi.org/10.7301/Z0J38QWF

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