PHOTOELECTRON SPECTROSCOPY AND COMPUTATIONAL STUDIES OF SIZE-SELECTED BORON, METAL BORIDE AND GOLD ALLOY CLUSTERS

Chen, Weijia

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Overview

Year:: 2023
Contributor:: Chen, Weijia (creator); Wang, Lai-Sheng (Advisor); Chen, Ou (Reader); Rubenstein, Brenda (Reader); Brown University. Department of Chemistry (sponsor)
Genre:: theses
Subject:: nanocluster; Chemistry, Physical and theoretical; Boron
Extent:: , None p.

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Abstract:: Atomic clusters are defined as aggregates of atoms, which serve as intermediates between individual atoms and bulk materials. Studying those atomic clusters can help us understand the chemical bonding between atoms, discover novel structures and molecules, and probe the evolution from atomic properties to those of bulk materials. This dissertation reports joint photoelectron spectroscopy and theoretical studies of size-selected boron, metal boride and gold alloy clusters to investigate their structural, electronic and bonding properties. Size-selected negatively-charged boron clusters (Bn−) have been found to be planar or quasi-planar in a wide size range. How the structures of larger boron clusters evolve is of immense interest. The research presented in this thesis reports the observation of a bilayer B48− cluster, showing the structural diversity of boron nanoclusters and provides experimental evidence for the viability of bilayer borophenes. Boron clusters doped with different metal atoms, including copper, bismuth, gold, and lead, are investigated, revealing the existence of numerous metal-borozene complexes and interesting metal-boron bonds. Cu2B8 is found to feature a Cu2+ dimer atop the B82 borozene surface, the bonding interaction is similar to what was observed in the growth of bilayer borophene. BiB6 is found to consist of a double-chain B6 with a terminal Bi atom. Both BiB7 and BiB8 are composed of a Bi atom bonded to the planar global minima of the B7 and B8 clusters. AuB8– possesses a chair-like structure with Au+ bonded to the edge of the B82– borozene. Furthermore, a boron monoxide cluster B9O is found to contain a 7-B7 ligand within an umbrella-like [(7-B7)-B-BO] structure, in which the central B atom exhibits transition-metal-like properties. PbB2O– is found to have an open-shell linear structure, where the bond order of Pb-B is 2.5 in anion and 3 in the corresponding neutral. PbB3O2– is shown to have a Y-shaped structure with a terminal B-Pb double bond coordinated by two boronyl ligands. A Zn-doped gold alloy cluster, Au9Zn, is also investigated. The global minimum of Au9Zn is found to be a Au10 triangle with its central Au atom replaced by Zn, its two sets of double σ aromaticity give rise to its remarkable stability.
Notes:: Thesis (Ph. D.)--Brown University, 2023

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Citation

Chen, Weijia, "PHOTOELECTRON SPECTROSCOPY AND COMPUTATIONAL STUDIES OF SIZE-SELECTED BORON, METAL BORIDE AND GOLD ALLOY CLUSTERS" (2023). Chemistry Theses and Dissertations. Brown Digital Repository. Brown University Library. https://repository.library.brown.edu/studio/item/bdr:vek4uwqf/

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Chemistry Theses and Dissertations

Theses and Dissertations for the Chemistry department.
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