Recent advances in experimental techniques now enable researchers to produce in a laboratory clusters of atoms of desired composition from any of the elements of the periodic table. This has created a new area of research into novel materials since clusters cannot be regarded either as a "large" molecule or as a fragment of the bulk. Both experimental and theoretical studies are revealing unusual properties that are not ob served in solid state environments. The structures of micro-clusters are found to be significantly distorted from the most symmetric arrangement, some even exhibiting pentagonal symmetry commonly found in icosahedric structures. The unusual stability of certain clusters, now described as "magic number species", shows striking similarities with the nuclear shell structure. The relative stabilities of clusters depend not only on the composition of the clusters but also on their charged states. The studies on spontaneous fragmentation of mUltiply charged clusters, commonly referred to as Coulomb explosion, illustrate the role of electronic bonding mechanisms on stability of clusters. The effect of foreign atoms on geometry and stability of clusters and the interaction of gas atoms with clusters are showing promise for an indepth understanding of chemisorption and catalysis. The magnetic and optical properties are dependent not only on cluster size but also on its geometry. These findings have the potential for aiding industry in the area of micro-electronics and catalysis.
Inhalt
Atomic Structure.- Photoelectron Spectroscopy of Metal Cluster Ion Beams.- Atomic Structure of Small Clusters: The Why and How of the Five-Fold Symmetry.- Study of Production Technique for Metallic Ultra Fine Particles Using Arc Energy.- Electron Diffraction Study of Supersonically Generated Clusters.- Control over the Structure of Clusters Generated in Supersonic Flow.- Annealing of Fine Powders: Initial Shapes and Grain Boundary Motion.- Continuous Mass Selected Cluster Ion Production using a Liquid Metal Ion Source.- Dangling Bonds Reconstruction at the Core of a 90° Partial Dislocation in Silicon: A Theoretical Study.- Isolation of Monodispersed Gold Clusters of Controlled Size.- Structures of C5 and C6.- The Structure of Small Gold Crystals.- Graph Theory Derived Methods for the Study of Metal Cluster Bonding Topology: Applications to Post-Transition Metal Clusters.- Laser Vaporization and Photoionization Studies of Tin and Lead Clusters.- Laser Vaporization and Photoionization of Group IV and V Intermetallic Clusters.- A Theoretical Study of Carbon Clusters: Equilibrium Geometries and Electronic Structures of Cn.- Multiphoton Stimulated Desorption: The Geometrical Structure of Neutral Sodium Chloride Clusters.- Mass and Temperature Measurement in Pure Vapor Expansion of Metals and Semi-Metals.- Fine Structure of Mass Spectrum of Sodium Clusters: Giant Atom Concept.- The X?(R) Method: A Semi-Empirical Method with a Varying with the Internuclear Distance.- Atomic Resolution Study of Structural Rearrangements in Metal Clusters.- A Fragment Cluster Study of Polyacetylene.- An Approximate Ab-Inito Theory of Metal Clusters.- Alkali Clusters: Structure, Stability, Large Amplitude Motion and Chemical Properties.- A Unified Explanation of Magic Numbers in Small Clusters.- Dynamics.- A Molecular Dynamics Study of Silicon Clusters.- Electron Localization and Excitation Dynamics in Small Clusters.- Melting and Freezing of Microclusters.- Structure and Melting of Argon Clusters on a Substrate.- Dynamics of Atomic Collisions on Helium Clusters.- Isomerization and Melting of Small Alkali-Halide Clusters.- Minimum Energy Structures of Br2-ArN Clusters: Implications for Dynamics.- Steepest Descent Quenches and the Melting of Microclusters.- Stability and Fragmentation.- Photofragmentation and Stability in Semiconductor Microcluster Ions.- Atomic and Electronic Structure of Semiconductor Clusters.- Magic Numbers of Alkali Halide Clusters.- Spectroscopy of Na3 and Experiments on Size-Selected Metal Cluster Ions.- Density Functional Calculation of the Fragmentation of Neutral, Singly and Doubly-Ionized Spherical Jellium-like Metallic Microparticles.- Experiments on Sputtered Clusters as Probe of Metal Cluster Ion Stability.- Velocity Measurements of Bismuth Clusters: Velocity Slip and Fragmentation Processes.- Fragmentation of Silicon Microclusters.- Spectroscopic Investigation of Ag-Metal Clusters.- Photofragmentation of Mass-Selected Main Group Element Cations.- Desorption and Decomposition of Multiply Charged Clusters from the Crystal of Group IV Elements by Laser Excitation.- Energy of Formation for Small Molecular Clusters: (H2O)n.- Energy Redistribution and Cluster Stability.- Fragmentation of Neutral and Ionic Carbon Clusters.- Production of Cluster Ions by Laser Vaporization.- From Metal Clusters to Cluster Metals.- Thermal Stability of Micro-Clusters.- Measurement of Bi2 and Bi4 Electron Impact Fragmentation Using Magnetic Polarization.- Metastable Decay of Photoionized Niobium Clusters: Evaporation vs Fission Fragmentation.- Electronic Structure and Properties.- ESR of Small Clusters.- Structure of Homo- and Hetero-Nuclear Micro-Clusters.- Stability of Small Metallic Clusters: Conceptual and Computational Challenges.- Self-Consistent Calculation of the Collective Excitations of Small Jellium Spheres.- Magnetic Properties of Molecular Metal Clusters.- Electronic Properties of Water Clusters by an Effective Hamiltonian Treatment.- An Ab-Initio Study of the Interaction of Atomic Hydrogen with Lithium Clusters.- The EPR Spectrum of Na3 in Adamantane.- Electronic Structure and Properties of Small Be Clusters.- Jahn-Teller Distortion, Hund's Coupling and Metastability in Alkali Teramers.- Electronic Structure of Small Carbon, Silicon, and Germanium Clusters.- Periodic Anderson Model for Small Clusters.- Electronic Theory of Segregation in Small Bimetallic Clusters.- Theoretical Cluster Model of a Zn-C Reformatsky Intermediate.- Calculation of the Magnetic Properties of Small Fe-Clusters.- Discussion of the Size Dependence of Ionization Threshold Energy of Fe Clusters.- Self-Interaction-Corrected Calculation of the Static Polarizability of Small Metal Spheres.- ESR and Electron Spin Relaxation Time T1, of Be Small Particles.- Electronic States and Geometrical Structures of Hubbard Clusters With an Impurity.- Theoretical Predictions of the Vibrational Frequencies of Singlet Li4.- Evaporation of Metal Clusters.- Analysis of the Basis Set Dependency on the Electronic Structure of Nb2.- Analysis of the Electronic Properties of Small Niobium Clusters.- Linearized Augmented Plane Wave (LAPW) Method for Isolated Clusters and Molecules.- The Nickel Dimer and Trimer.- Optical Properties.- Inelastic Light Scattering from Metal Clusters: Some Recent Developments.- Optical and Infrared Properties of Small Metal Particles.- Cluster Spectroscopy: Variations in Ionization Potentials and Spectral Shifts as a Function of Degree of Aggregation and Studies of Cluster Fragmentation.- Trapping Sites and Vibrational Modes of Ag2 in Rare Gas Matrices: A Computer Simulation.- Laser-Induced Fluorescence and Raman Investigations of Agn(n?.4) by Means of Matrix Isolation Spectroscopy.- Photoelectron Spectroscopy of Molecular Clusters: N2 and N2O.- Multipolar Excitations in Small Metallic Spheres.- Theory of Damping of Excited States of a Molecule Near a Metallic Cluster.- Photoinduced Aggregation and Dissociation of Ag and Au Clusters in Rare Gas Matrices.- Magneto-Optical Investigation of Mn and Cu-Mn Small Clusters Embedded in Rare Gas Matrices.- Van Der Waals Clusters.- Multiply Charged Clusters.- Collisional Electron Transfer to Neutral Clusters by High Rydberg Rare Gas Atoms.- Solvation of Alkali Halides in Alcohol Clusters.- On the Electronic Structure of a Singly Ionized Cluster Composed of Closed Shell Atoms or Molecules.- Unimolecular Decay of Small NH3 Cluster Ions.- El…