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Title: Copper at the nanoscale : computational studies of clusters, surfaces and surface interactions
Author: Daff, Thomas Duncan
Awarding Body: Birkbeck (University of London)
Current Institution: Birkbeck (University of London)
Date of Award: 2010
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Size, shape and structure control of copper nanoparticles has been achieved through chemical synthesis methods, although only at an empirical level. An understanding of the processes involved at the molecular level will enable a finer control over the particles that are produced. Using interatomic potential methods, the (111) surface of copper is demonstrated to be the most stable both in the ground state, and with respect to surface melting. The addition of low-coordinated sites initiates melting at lower temperatures, although the terraces remain stable. The most stable particle shapes, whilst fairly spherical, still show a dominance of (111) faces. The growth modifying properties of hydrazine, the reducing agent, are modelled by surface adsorption using ab initio methods. Gas phase adsorption shows stronger binding to the (100) surface than the (111) surface. The strongest adsorptions are on the (110) surface, where the rougher structure accommodates bridging geometries, and low-coordinated adatoms provide sites for stronger adsorption on the planar surfaces. Dissociation of the molecule is thermodynamically favoured. The gas phase studies do not fully explain the synthesis. Instead, explicit treatment of the hydration shell with first-principles dynamics simulations predicts adsorption on the (111) surface, but not on the (100) surface. The preferential binding provides a consistent rationalisation of the experimental method.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available