Electronic And Structural Properties Of Nanoclusters

Nanoclusters have gained a huge interest due to their unique properties. They represent an intermediate state between an atom and a solid, which manifests itself in their atomic configurations and electronic structure. The applications of nanoclusters require detailed understanding of their properties and strongly depend on the ability to control their synthesis process. Significant effort has been invested in modelling of nanoclusters properties. However, the complexity of these systems is such that many aspects of their growth process and properties are yet to be understood. My thesis focuses on describing structural and electronic properties of nanoclusters. In particular, the model for nanoparticles growth in plasma condition is developed and applied, allowing to describe the influence of the plasma conditions on the evaporation, growth and morphological transformation processes. The mechanism driving the morphology transition from icosahedral to decahedral phase is suggested based on force-fields models. Spectroscopic methods allow for precise characterization of nanoclusters and constitute an important tool for analysis of their electronic structure of valence band as well as core-states. The special attention in the thesis is paid to the core-states of nanoclusters and influences that affect them. In particular, the effects of local coordination, interatomic distances and confinement effects are investigated in metal nanoclusters by density functional theory methods. These effects and their contribution to spectroscopic features of nanoclusters in X-ray photoemission are modelled. The relation between the reactivity of nanoclusters and their spectroscopic features calculated in different approximations are revealed and explained. Ceria is a very important system for many applications due to the ability of cerium atoms to change their oxidation state depending on the environment. The shift of the oxidation state and its effects on the core-states is examined with X-ray absorption measurements and modelling allowing to build a rigid foundation for interpretation of the measured spectra and characterization of electronic structure of ceria nanoparticles.

Atomic clusters are aggregates of atoms containing a few to several thousand atoms. Due to the small size of these pieces of matter, the properties of atomic clusters in general are different from those of the corresponding material in the macroscopic bulk phase. This monograph presents the main developments of atomic clusters and the current status of the field. The book treats different types of clusters with very different properties: clusters in which the atoms or molecules are tied by weak van der Waals interactions, metallic clusters, clusters of ionic materials, and network clusters made of typical covalent elements. It includes methods of experimental cluster synthesis as well as the structural, electronic, thermodynamic and magnetic properties of clusters, covering both experiments and the theoretical work that has led to our present understanding of the different properties of clusters. The question of assembling nanoclusters to form solids with new properties is also considered. Having an adequate knowledge of the properties of clusters can be of great help to any scientist working with objects of nanometric size. On the other hand, nanoclusters are themselves potentially important in fields like catalysis and nanomedicine.

Atomic clusters are aggregates of atoms containing a few to several thousand atoms. Due to the small size of these pieces of matter, the properties of atomic clusters in general are different from those of the corresponding material in the macroscopic bulk phase. This monograph presents the main developments of atomic clusters and the current status of the field. The book treats different types of clusters with very different properties: clusters in which the atoms or molecules are tied by weak van der Waals interactions, metallic clusters, clusters of ionic materials, and network clusters made of typical covalent elements. It includes methods of experimental cluster synthesis as well as the structural, electronic, thermodynamic and magnetic properties of clusters, covering both experiments and the theoretical work that has led to our present understanding of the different properties of clusters. The question of assembling nanoclusters to form solids with new properties is also considered. Having an adequate knowledge of the properties of clusters can be of great help to any scientist working with objects of nanometric size. On the other hand, nanoclusters are themselves potentially important in fields like catalysis and nanomedicine.

This volume on Clusters brings together contributions from a large number of specialists. A central element for all contributions is the use of advanced computational methodologies and their application to various aspects of structure, reactivity and properties of clusters. The size of clusters varies from a few atoms to nanoparticles. Special emphasis is given to bringing forth new insights on the structure and properties of these systems with an eye towards potential applications in Materials Science. Overal, the volume presents to the readers an amazing wealth of new results. Particular subjects include water clusters, Silicon, Iron, Nickel and Gold clusters, carbon-titanium microclusters and nanoparticles, fullerenes, carbon nanotubes, chiral carbon nanotubes, boron nanoclusters and more.

The primary goal of nanotechnology is to achieve nanoscale materials and devices with atomic precision. Toward this goal, breakthroughs have recently been made in the solution-phase synthesis and applications of atomically precise nanoclusters. This book presents the exciting progress in this new research field. The chapters are contributed by leading experts of the field and cover the synthetic methods, atomic structures, electronic and optical properties, and catalytic applications of noble metal nanoclusters. Such new nanocluster materials offer exciting opportunities for chemists and physicists to understand the fundamental science of nanoclusters, especially the atomic-level structure–property correlation and design of new materials, as well as for developing a range of applications including catalysis, biomedicine, sensing, imaging, optics, and energy conversion. The book will be of interest to readers and researchers in nanotechnology, nanochemistry, catalysis, and computational chemistry, as well as practitioners in industry R&D for new materials. It is written to be accessible to undergraduate and graduate students and, therefore, is an excellent teaching material.

Bimetallic nanoparticles, also called nanoalloys, are at the heart of nanoscience because of their ability to tune together composition and size for specific purposes. By approaching both their physical and chemical properties, Nanoalloys: Synthesis, Structure & Properties provides a comprehensive reference to this research field in nanoscience by addressing the subject from both experimental and theoretical points of view, providing chapters across three main topics: Growth and structural properties Thermodynamics and electronic structure of nanoalloys Magnetic, optic and catalytic properties The growth and elaboration processes which are the necessary and crucial part of any experimental approach are detailed in the first chapter. Three chapters are focused on the widely used characterization techniques sensitive to both the structural arrangements and chemistry of nanoalloys. The electronic structure of nanoalloys is described as a guide of useful concepts and theoretical tools. Chapters covering thermodynamics begin with bulk alloys, going to nanoalloys via surfaces in order to describe chemical order/disorder, segregation and phase transitions in reduced dimension. Finally, the optical, magnetic and catalytic properties are discussed by focusing on nanoparticles formed with one element to track the modifications which occur when forming nanoalloys. The range and detail of Nanoalloys: Synthesis, Structure & Properties makes it an ideal resource for postgraduates and researchers working in the field of nanoscience looking to expand and support their knowledge of nanoalloys.

Atomically precise metal nanoclusters occupy the gap between discrete atoms and plasmonic nanomaterials, and they offer intriguing physical-chemical properties that can be rationalized in terms of their quantum size effects and discrete electronic states. The atomically precise nature of their structures lends them well to structure-property relationship elucidation, making them particularly useful for informing the rational design of nanoclusters with enhanced performance. Metal Nanocluster Chemistry: Ligand-Protected Metal Nanoclusters With Atomic Precision provides a concise introduction to the study of these useful nanoclusters. Beginning with an introduction to the fundamental concepts of, and prospects for, metal nanoclusters, the book goes on to highlight synthetic methods for controllable preparation. The subsequent chapters then highlight characterization, mechanism of size growth and structure evolution, and physical-chemical properties. Later chapters examine theoretical approaches for calculating and evaluating structures and properties. They also highlight the assembly of nanocluster building blocks and their practical applications. Drawing on the knowledge of its expert author, Metal Nanocluster Chemistry is a useful introductory guide to these exciting structures. Provides a concise introduction to atomically-precise metal nanoclusters, ranging from characterization and property investigation to applications Includes insight into both current trends and future potential, encouraging and supporting further development Holistically combines physical approaches with theoretical calculation methods