Optics and Structure of Metal Clusters at the Atomic Scale

Optics and Structure of Metal Clusters at the Atomic Scale PDF Author: Alfredo Campos Otero
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
It is well known that the optical properties of nanoparticles of noble metals, in particular gold and silver, deviate strongly from those of macroscopic metals. For sizes between ten and a few hundred nanometers, they are dominated by surface plasmons (SPs) described by purely classical models. On the other hand, clusters of a few tens of atoms behave like quantum systems inducing new optical behaviors. The structure of the nanoparticles and the dielectric environment can affect the optical properties. In this thesis I used a scanning transmission electron microscope (STEM) fitted with an electron energy loss spectrometer (EELS) to measure, in parallel, the optical and structural properties of individual nanoparticles. I present how complementary experiments (STEM-EELS and optical absorption) on sizeselected small silver nanoparticles embedded in silica yield at first inconsistent results: while optical absorption shows no size-effect in the range between only a few atoms and ~10 nm, a clear spectral shift is observed in STEM-EELS technique. Our quantitative interpretation, based on a mixed classical/quantum model which takes into account all the relevant quantum effects, resolves the apparent contradictions, not only within our experimental data, but also in the literature. Our comprehensive model describes how the local environment is the crucial parameter controlling the manifestation or absence of quantum size effects. Secondly, I was interested in the purely classical region through lithographed structures of a few hundred nanometers. Although triangular plasmonic cavities have been widely studied in the literature, a classification in terms of plasmonic modes of breathing and edge was missing. In this study, experimental STEM-EELS results, analytical models and classical simulations enabled us to describe the nature of the different modes.

Optics and Structure of Metal Clusters at the Atomic Scale

Optics and Structure of Metal Clusters at the Atomic Scale PDF Author: Alfredo Campos Otero
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

Get Book Here

Book Description
It is well known that the optical properties of nanoparticles of noble metals, in particular gold and silver, deviate strongly from those of macroscopic metals. For sizes between ten and a few hundred nanometers, they are dominated by surface plasmons (SPs) described by purely classical models. On the other hand, clusters of a few tens of atoms behave like quantum systems inducing new optical behaviors. The structure of the nanoparticles and the dielectric environment can affect the optical properties. In this thesis I used a scanning transmission electron microscope (STEM) fitted with an electron energy loss spectrometer (EELS) to measure, in parallel, the optical and structural properties of individual nanoparticles. I present how complementary experiments (STEM-EELS and optical absorption) on sizeselected small silver nanoparticles embedded in silica yield at first inconsistent results: while optical absorption shows no size-effect in the range between only a few atoms and ~10 nm, a clear spectral shift is observed in STEM-EELS technique. Our quantitative interpretation, based on a mixed classical/quantum model which takes into account all the relevant quantum effects, resolves the apparent contradictions, not only within our experimental data, but also in the literature. Our comprehensive model describes how the local environment is the crucial parameter controlling the manifestation or absence of quantum size effects. Secondly, I was interested in the purely classical region through lithographed structures of a few hundred nanometers. Although triangular plasmonic cavities have been widely studied in the literature, a classification in terms of plasmonic modes of breathing and edge was missing. In this study, experimental STEM-EELS results, analytical models and classical simulations enabled us to describe the nature of the different modes.

Structure and Properties of Atomic Nanoclusters

Structure and Properties of Atomic Nanoclusters PDF Author: Julio A. Alonso
Publisher: World Scientific
ISBN: 1848167334
Category : Science
Languages : en
Pages : 492

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Book Description
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.

Optical Properties of Metal Clusters

Optical Properties of Metal Clusters PDF Author: Uwe Kreibig
Publisher: Springer Science & Business Media
ISBN: 3662091097
Category : Technology & Engineering
Languages : en
Pages : 552

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Book Description
Optical Properties of Metal Clusters deals with the electronic structure of metal clusters determined optically. Clusters - as state intermediate between molecules and the extended solid - are important in many areas, e.g. in air pollution, interstellar matter, clay minerals, photography, heterogeneous catalysis, quantum dots, and virus crystals. This book extends the approaches of optical molecular and solid-state methods to clusters, revealing how their optical properties evolve as a function of size. Cluster matter, i.e. extended systems of many clusters - the most frequently occuring form - is also treated. The combination of reviews of experimental techniques, lists of results and detailed descriptions of selected experiments will appeal to experts, newcomers and graduate students in this expanding field.

Atomically Precise Metal Clusters

Atomically Precise Metal Clusters PDF Author: Shuang-Quan Zang
Publisher: John Wiley & Sons
ISBN: 352784208X
Category : Science
Languages : en
Pages : 338

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Book Description
Atomically Precise Metal Clusters Thorough discussion on how surface modification and self-assembly play roles in the atomically precise formation and property tailoring of molecular clusters Atomically Precise Metal Clusters: Surface Engineering and Hierarchical Assembly summarizes and discusses the surface modification, assembly, and property tailoring of a wide variety of nanoclusters, including the well-explored metal clusters, addressing the structure–property relationships throughout. The atomic-level control in synthesis, new types of structures, and physical/chemical properties of nanoclusters are illustrated in various chapters. The controlled modification and assembly of metal nanoclusters is expected to have a major impact on future nanoscience research and other areas, with distinctive metal cluster-based function materials with precise structures uncovering exciting opportunities in both fundamental research and practical applications. Written by a highly qualified academic with significant research experience in the field, Atomically Precise Metal Clusters includes information on: Ligand engineering and assembly of coinage metal nanoclusters such as gold, silver, and copper Recent advances in post-modification of polyoxometalates and small transition metal chalcogenide superatom clusters Synthesis and assembly of cadmium chalcogenide supertetrahedral clusters and modification and assembly of Fe-S clusters Indium phosphide magic-sized clusters, ligand-tailoring platinum and palladium clusters, and metal oxo clusters (MOCs) Enabling access to desired functions in metal clusters for catalysis, optics, biomedicine, and other fields through surface engineering and supramolecular assembly A timely and comprehensive book that summarizes the recent progress in the surface modification and self-assembly of metal nanoclusters, Atomically Precise Metal Clusters provides essential guidance for graduate students and advanced researchers in material science, chemistry, biomedicine, and other disciplines.

Atomically Precise Metal Nanoclusters

Atomically Precise Metal Nanoclusters PDF Author: Zhikun Wu
Publisher: Springer Nature
ISBN: 3031023897
Category : Science
Languages : en
Pages : 129

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Book Description
Atomically precise metal nanocluster research has emerged as a new frontier. This book serves as an introduction to metal nanoclusters protected by ligands. The authors have summarized the synthesis principles and methods, the characterization methods and new physicochemical properties, and some potential applications. By pursuing atomic precision, such nanocluster materials provide unprecedented opportunities for establishing precise relationships between the atomic-level structures and the properties. The book should be accessible to senior undergraduate and graduate students, researchers in various fields (e.g., chemistry, physics, materials, biomedicine, and engineering), R&D scientists, and science policy makers.

Atomically Precise Nanoclusters

Atomically Precise Nanoclusters PDF Author: Rongchao Jin
Publisher: CRC Press
ISBN: 1000246396
Category : Science
Languages : en
Pages : 346

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Book Description
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.

Metal Clusters at Surfaces

Metal Clusters at Surfaces PDF Author: Karl-Heinz Meiwes-Broer
Publisher: Springer Science & Business Media
ISBN: 9783540665625
Category : Science
Languages : en
Pages : 332

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Book Description
Numerous experiments and calculations have shown that isolated metal clusters possess many interesting features, quite different from those known from surface and solid- state physics or from atomic and molecular physics. The technological exploitation of these new properties, e.g. in miniature electronic or mechanical components, requires the cluster to be brought into an environment such as an encapsulating matrix or a surface. Due to the interaction with the contact medium, the properties of the clusters may change or even disappear. Thus the physics of cluster-on-surface systems -- the main subject of this book -- is of fundamental importance. The book addresses a wide audience, from the newcomer to the expert. Starting from fundamental concepts of adsorbate-surface interactions, the modification of electronic properties through electron confinement, and concepts of cluster production, it elucidates the distinct properties of the new metallic nanostructures.

Metal Clusters at Surfaces

Metal Clusters at Surfaces PDF Author: Karl-Heinz Meiwes-Broer
Publisher: Springer Science & Business Media
ISBN: 3642571697
Category : Science
Languages : en
Pages : 315

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Book Description
Due to the interaction with the contact medium, the properties of clusters may change or even disappear. Thus the physics of cluster-on-surface systems -- the main subject of this book -- is of fundamental importance. The book addresses a wide audience, from the newcomer to the expert. Starting from fundamental concepts of adsorbate-surface interactions, the modification of electronic properties through electron confinement, and concepts of cluster production, it elucidates the distinct properties of the new metallic nanostructures.

Atomic and Molecular Clusters

Atomic and Molecular Clusters PDF Author: Roy L. Johnston
Publisher: CRC Press
ISBN: 9781420055771
Category : Science
Languages : en
Pages : 258

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Book Description
Cluster physics is the foundation of the increasingly important field of nanotechnology. Clusters, ranging in size from a few to many millions of atoms, constitute a fascinating field of research in physics, chemistry and materials science. They are formed by most of the elements of the Periodic Table, and the types of bonding and the resultant clusters are equally as varied. This book introduces atomic clusters, ranging from weakly-bonded clusters of argon to strongly-bonded carbon clusters and metal nano-particles. It includes worked examples to enable lecturers and students to gauge their understanding and progress. Atomic and Molecular Clusters describes the experimental generation, detection and interrogation of clusters and theoretical approaches developed to aid understanding of their physical properties. It classifies clusters according to their bonding types and gives examples of present and possible future applications of clusters in electronic, optical and magnetic devices.

Atomic Scale Dynamics at Surfaces

Atomic Scale Dynamics at Surfaces PDF Author: Giorgio Benedek
Publisher: Springer
ISBN: 3662564432
Category : Science
Languages : en
Pages : 625

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Book Description
Experimental advances in helium atom scattering spectroscopy over the last forty years have allowed the measurement of surface phonon dispersion curves of more than 200 different crystal surfaces and overlayers of insulators, semiconductors and metals. The first part of the book presents, at a tutorial level, the fundamental concepts and methods in surface lattice dynamics, and the theory of atom-surface interaction and inelastic scattering in their various approximations, up to the recent electron-phonon theory of helium atom scattering from conducting surfaces. The second part of the book, after introducing the experimentalist to He-atom spectrometers and the rich phenomenology of helium atom scattering from corrugated surfaces, illustrates the most significant experimental results on the surface phonon dispersion curves of various classes of insulators, semiconductors, metals, layered crystals, topological insulators, complex surfaces, adsorbates, ultra-thin films and clusters. The great potential of helium atom scattering for the study of atomic scale diffusion, THz surface collective excitations, including acoustic surface plasmons, and the future prospects of helium atom scattering are presented in the concluding chapters. The book will be valuable reading for all researchers and graduate students interested in dynamical processes at surfaces.