Metal Clusters at Surfaces : Structure, Quantum Properties, Physical Chemistry

The book addresses a wide audience, from the beginner in this field to the expert. Starting from fundamental concepts of adsorbate - surface interactions, the modification of electronic properties through electron confinement as well as concepts of cluster production, the book will deal with very distinct properties of the new metallic nanostructures.

1 Confinement and Size Effects in Free Metal Clusters.- 1.1 Introduction.- 1.2 Free Simple Metal Clusters.- 1.2.1 The Shell Model.- 1.2.2 Extended Theoretical Models.- 1.2.3 Liquid and Solid Clusters.- 1.2.4 Molecular Beam Methods for Cluster Research.- 1.2.5 Electronic and Geometrical Structure.- 1.2.6 Optical Excitations and Plasma Resonances.- 1.3 Magnetic Particles in Molecular Beams.- 1.3.1 Stern-Gerlach Deflections of Ferromagnetic Metal Clusters.- 1.3.2 Magnetic Moments of 3d Transition Metal Clusters.- 1.3.3 Other Ferromagnetic Cluster Systems.- 1.4 Conclusion.- 2 Fundamentals of Adsorbate-Surface Interactions.- 2.1 Introduction.- 2.2 Physisorption of Xenon on Graphite: Superstructure and Domain Boundaries.- 2.3 Chemisorption of Alkali Atoms on Semiconductor Surfaces.- 2.3.1 Ionic vs. Covalent Bonding and Charge-Transfer Monitoring.- 2.3.2 Li, Na, K and Cs on Cleaved Si(111).- 2.3.3 Li, Na, K and Rb on Si(100).- 2.4 Bonding of C60 Molecules on Ag and Au(110) Surfaces.- 2.4.1 Geometric Properties.- 2.4.2 Electronic Properties.- 2.5 Electronic Response within the Cluster-Surface Interaction.- 2.6 Summary.- 3 Growth of Metal Clusters at Surfaces.- 3.1 Introduction.- 3.2 The Elementary Processes of MBE Growth.- 3.3 Nucleation.- 3.4 Aggregation.- 3.5 Coarsening.- 3.6 Anisotropic Surfaces.- 3.7 Growth of Cluster Arrays.- 3.8 Single Crystal Oxide Surfaces.- 3.9 Conclusion.- 4 Collision of Clusters with Surfaces.- 4.1 Introduction.- 4.2 Cluster-Surface Collisions: General Remarks.- 4.3 Experimental Considerations.- 4.4 Molecular Dynamics Calculations.- 4.5 Softlanding..- 4.6 Fragmentation.- 4.6.1 Clusters Scattering off the Surface.- 4.6.2 Fragmentation Studies on Molecules and Clusters.- 4.7 Implantation.- 4.8 Sputtering.- 4.9 Thin Film Formation by Energetic Cluster Impact.- 4.10 Cluster Impact Chemistry.- 4.11 Crater Formation and Cluster Impact Induced Erosion.- 4.12 Electronic Processes.- 4.13 Summary and Outlook.- 5 Electronic Level Structure of Metal Clusters at Surfaces.- 5.1 Introduction.- 5.2 Photoelectron Spectroscopy of Deposited Clusters.- 5.3 Scanning Tunnelling Spectroscopy and Inverse Photoemission.- 5.3.1 Target Preparation and Experimental Methods.- 5.3.2 STS on Platinum, Silver and Sodium Clusters.- 5.3.3 Photon Maps of Silver Islands.- 5.4 Summary.- 6 Conductance Quantisation in Metallic Point Contacts.- 6.1 Introduction.- 6.2 Landauer Theory for Ballistic Conductance.- 6.3 Experimental Techniques.- 6.4 Conductance of Atomic-Scale Contacts.- 6.5 Histograms of Conductance Values.- 6.6 The Character of the Conductance Modes Through a Single Atom.- 6.6.1 Subgap Structure in Superconducting Contacts.- 6.6.2 Valence-Orbital-Based Description of the Conductance Modes.- 6.6.3 Further Experimental Techniques.- 6.6.4 Implications for Conductance Curves and Histograms.- 6.7 Chains of Atoms.- 6.8 Quantum Forces and Shell Structure in Alkali Nanowires.- 6.9 Discussion and Outlook.- 7 Magnetism of Nanometer-Sized Particles and Clustersr.- 7.1 Introduction.- 7.2 Single Particle Measurement Techniques.- 7.2.1 Micro-SQUID Magnetometry.- 7.3 Mechanisms of Magnetisation Reversal in Single Domain Particles at Zero Kelvin.- 7.3.1 Magnetisation Reversal by Uniform Rotation.- 7.3.2 Generalisation of the Stoner-Wohlfarth Model.- 7.3.3 Experimental Verification.- 7.4 Influence of Temperature on Magnetisation Reversal.- 7.4.1 Superparamagnetism — Néel-Brown Model.- 7.4.2 Experimental Methods.- 7.4.3 Experimental Evidence for the Néel-Brown Model.- 7.5 Magnetisation Reversal by Quantum Tunnelling.- 7.5.1 Molecular Clusters.- 7.5.2 Individual Single-Domain Nanoparticles.- 7.5.3 Single-Domain Nanoparticles and Wires at Low Temperatures.- 8 Physical Chemistry of Supported Clusters.- 8.1 Introduction.- 8.2 Supported Size-Distributed Model Catalysts.- 8.2.1 Preparation and Characterisation.- 8.2.2 CO Dissociation on Supported Rh Clusters.- 8.2.3 Kinetic Effects in the CO Oxidation Reaction on Supported Pd Particles.- 8.2.4 Catalytic Activity of Supported Au Clusters.- 8.3 Supported Monodispersed Model Catalysts.- 8.3.1 Preparation and Characterisation of Monodispersed Supported Clusters.- 8.3.2 Size-Dependent CO Dissociation on Small Ni Clusters.- 8.3.3 The Catalytic Role of Small Silver Clusters for the Latent Image Generation in Photography.- 8.3.4 The Hydrogenation of Toluene on Monodispersed Ir4 and Ir6 Supported on Oxide Surfaces.- 8.3.5 Size-Dependent Cyclotrimerisation of Acetylene on Monodispersed Palladium Clusters Supported on MgO.- 8.3.6 The Oxidation of CO on Monodispersed Platinum Clusters Supported on MgO.- 8.3.7 The Oxidation of CO on Monodispersed Gold Clusters Supported on MgO.- 8.4 Conclusions and Outlook.- 9 Application of Clusters to the Fabrication of Silicon Nanostructures.- 9.1 Prospects for the Application of Clusters.- 9.1.1 Clusters as Building Blocks.- 9.1.2 Clusters as Tools.- 9.2 Silicon Nanostructures.- 9.2.1 Motivation.- 9.2.2 Experimental Approaches.- 9.3 Production of Cluster Films for Fabrication.- 9.3.1 Cluster Growth on Surfaces.- 9.3.2 Deposition of Size-Selected Clusters.- 9.3.3 Organised Arrays of Clusters.- 9.4 Application of Metal Clusters as Plasma Etching Masks.- 9.4.1 Fabrication of Silicon Pillars and Cones using Cluster Films Grown on the Surface.- 9.4.2 Production of Silicon Pillars Using Cluster Beam Deposition.- 9.4.3 Ordered Arrays of Silicon Pillars.- 9.5 Summary.