Microcluster Physics

ISBN-13: 9783642973321 / Angielski / Miękka / 2012 / 158 str.

Satoru Sugano; J. Peter Toennies

Opis

This book aims at providing graduate students and researchers with funda- mental knowledge indispensable for entering the new field of "microclus- 3 ters." Microclusters consisting of 10 to 10 atoms exhibit neither the pro- perties of the corresponding bulk nor those of the corresponding molecule of a few atoms. The microclusters may be considered to form a new phase of materials lying between macroscopic solids and microscopic particles such as atoms and molecules, showing both macroscopic and microscopic features. However, research into such"a riew phase has been left untouched until recent years by the development of the quantum theory of matter. The microscopic features of microclusters were first revealed by ob- serving anomalies of the mass spectrum of a Na cluster beam at specific sizes, called magic numbers. Then it was experimentally confirmed that the magic numbers come from the shell structure of valence electrons. Being stimulated by these epoch-making findings in metal microclusters and aided by progress of the experimental techniques producing relatively dense, non- interacting micro clusters of various sizes in the form of micro cluster beams, the research field of microclusters has developed rapidly in these 5 to 7 years. The progress is also due to the improvement of computers and com- putational techniques, which have made it possible to perform ab initio cal- culations of the atomic and electronic structure of smaller microclusters, as well as to carry out computer simulations of their dynamics.

Spis treści

1. What are Microclysters?.- 1.1 Constituent Small Particles of Material.- 1.2 Division of Materials.- 1.2.1 Fine Particles.- 1.2.2 Microclusters.- 1.2.3 Molecules.- 2. Dynamics of Atomic Structure.- 2.1 Solid-like, Liquid-like, or Fluctuating?.- 2.1.1 Naive Questions.- 2.1.2 Atomic Structure of Adsorbed Microclusters.- 2.2 Coexistence of Solid-like and Liquid-like Phases.- 2.3 Fluctuating States and Permutation Isomers.- 2.3.1 The Case of N = 6.- 2.3.2 The Case of N = 7.- 2.3.3 Fluctuation in Large Clusters.- 2.4 Monte Carlo Simulations.- 2.4.1 Lennard-Jones Clusters Constrained to Spherical Cavities.- 2.4.2 Transition-Metal Clusters of N = 7–17.- 2.4.3 Effect of Magnetic Interactions.- 3. Shell Structure of Metal Clusters.- 3.1 Magic Numbers.- 3.2 The Jellium Model.- 3.2.1 Electronic Structure of NaN Clusters.- 3.2.2 Spin Polarization and Multiplet Formation.- 3.2.3 Nonspherical Perturbation.- 3.3 Theory of Shell Correction.- 3.3.1 Essence of the Theory.- 3.3.2 Shell Correction for the Harmonic-Oscillator Model.- 3.4 Deformation.- 3.4.1 Application of the Shell Correction Theory.- 3.4.2 Fine Structure of Mass Spectra.- 3.5 Fragmentation.- 3.5.1 Symmetric Fission of a Charged Liquid-Droplet.- 3.5.2 Shell Correction for a Necked Spheroidal Cluster.- 4. Other Properties of Metal Clusters.- 4.1 Nonempirical Calculation of Alkali-Metal Clusters.- 4.1.1 Generalization of Hellmann-Feynman Forces.- 4.1.2 Geometries Calculated.- 4.1.3 Comparison with Experiments.- 4.1.4 Nature of Binding.- 4.2 Electronic Structure of Noble-Metal Clusters.- 4.2.1 Energy Levels of Copper Clusters.- 4.2.2 Photoelectron Spectra of a Copper Cluster.- 4.3 Electronic Structure of Transition-Metal Clusters.- 4.3.1 Energy Levels of Nickel Clusters.- 4.3.2 Stern-Gerlach’s Experiment on Iron Clusters.- 4.4 Divalent-Metal Clusters.- 4.5 Trivalent-Metal Clusters, AlN.- 4.5.1 Observed Properties.- 4.5.2 Nonempirical Calculation of Al2-Al6.- 5. Semiconductor Clusters.- 5.1 Carbon Clusters.- 5.1.1 Mass Spectra.- 5.1.2 Nonempirical Calculation.- 5.2 Stabilities of Silicon and Germanium Clusters.- 5.2.1 Photofragmentation of Mass-Resolved Si2+-Si12+.- 5.2.2 Photofragmentation of Larger Silicon and Germanium Clusters.- 5.2.3 Highly Ionized Germanium Clusters.- 5.3 Nonempirical Calculations for Si6 and Si10.- 5.3.1 Equilibrium Geometries.- 5.3.2 Energy Levels.- 5.3.3 Density Distribution of Electrons.- 5.4 Force and Virial Analysis of Larger Silicon Clusters.- 5.4.1 Six-Membered-Ring Clusters.- 5.4.2 Triangle Contraction.- 6. Rare-Gas Clusters.- 6.1 The Magic Numbers for Packing.- 6.1.1 Xenon Clusters.- 6.1.2 Argon Clusters.- 6.2 Helium Clusters.- 6.2.1 Magic Numbers.- 6.2.2 Nonempirical Calculation.- 7. Molecular Clusters.- 7.1 Photoionization of Ammonia Clusters.- 7.2 Ion-Centered Cage Structure.- 7.2.1 Magic Numbers for Water Clusters.- 7.2.2 Monte-Carlo Calculations.- 7.3 Negatively Charged Water Clusters.- 7.3.1 Solvated Electrons.- 7.3.2 Trapping of Electrons.- 7.3.3 Theoretical Treatments.- 7.4 Electron Attachment to van der Waals Clusters.- 7.4.1 Electron Transfer from High-Rydberg Rare Gas Atoms.- 7.4.2 Strongly Coupled Electron-Phonon Model.- 8. Miscellaneous Topics.- 8.1 Synthetic Chemistry in a Cluster Beam.- 8.2 Latent-Image Generation.- 8.3 Electron Correlation and Chemical Bonds.- 8.3.1 Dimers Versus Close-Packed Aggregates.- 8.3.2 Trimers of Monovalent Elements.- 8.3.3 Pseudorotation of Na3.- 8.4 Van der Waals and Metallic Mercury Clusters.- 8.5 Prospects of Microcluster Research.- References.