Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.575594
Title: Theoretical studies of free and supported nanoalloy clusters
Author: Ismail, Ramli
Awarding Body: University of Birmingham
Current Institution: University of Birmingham
Date of Award: 2013
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Abstract:
Nanoclusters offer unique physical and chemical behaviour, with the possibility of fine-tuning size and structures. Detailed theoretical studies can extend our understanding of these complicated systems. In this research, a good balance between accuracy and computational cost in describing electronic structure was sought via a combined Empirical Potential (EP) - Density Functional Theory (DFT) method. Global optimisation searches were performed using the Birmingham Cluster Genetic Algorithm and Basin-Hopping Monte Carlo algorithm coupled with the semi-empirical Gupta potentials. The sensitivity of the potentials was further studied for various potential parameterisations. Exploration of Pd-Au, Pd-Pt and Ni-Al clusters evidence the polyicosahedra – decahedra – face-centered cubic transitions, but below 50 atoms, these motifs are energetically very competitive, which led to a detailed structural study for the 34- and 38-atom clusters, as a function of composition. A qualitatively good agreement between EP and DFT was found, with a prevalence towards coreshell Dh\(_3\)\(_4\) and TO\(_3\)\(_8\) structure for Pd-Au and Pd-Pt clusters. The performance of empirical calculations varies with composition. On an MgO support, Pd-Au clusters showed significant size and composition effects. Consistent with the available experimental findings, Pd atoms preferentially bind to the oxygen sites at the interface and good cluster-substrate epitaxy was observed.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.575594  DOI: Not available
Keywords: QD Chemistry
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