The Effective Crystal Field Potential

The Effective Crystal Field Potential PDF Author: J. Mulak
Publisher: Elsevier
ISBN: 0080530710
Category : Science
Languages : en
Pages : 319

Get Book Here

Book Description
As it results from the very nature of things, the spherical symmetry of the surrounding of a site in a crystal lattice or an atom in a molecule can never occur. Therefore, the eigenfunctions and eigenvalues of any bound ion or atom have to differ from those of spherically symmetric respective free ions. In this way, the most simplified concept of the crystal field effect or ligand field effect in the case of individual molecules can be introduced. The conventional notion of the crystal field potential is narrowed to its non-spherical part only through ignoring the dominating spherical part which produces only a uniform energy shift of gravity centres of the free ion terms. It is well understood that the non-spherical part of the effective potential "seen" by open-shell electrons localized on a metal ion plays an essential role in most observed properties. Light adsorption, electron paramagnetic resonance, inelastic neutron scattering and basic characteristics derived from magnetic and thermal measurements, are only examples of a much wider class of experimental results dependent on it. The influence is discerned in all kinds of materials containing unpaired localized electrons: ionic crystals, semiconductors and metallic compounds including materials as intriguing as high-Tc superconductors, or heavy fermion systems. It is evident from the above that we deal with a widespread effect relative to all free ion terms except those which can stand the lowered symmetry, e.g. S-terms. Despite the universality of the phenomenon, the available handbooks on solid state physics pay only marginal attention to it, merely making mention of its occurrence. Present understanding of the origins of the crystal field potential differs essentially from the pioneering electrostatic picture postulated in the twenties. The considerable development of the theory that has been put forward since then can be traced in many regular articles scattered throughout the literature. The last two decades have left their impression as well but, to the authors' best knowledge, this period has not been closed with a more extended review. This has also motivated us to compile the main achievements in the field in the form of a book.

The Effective Crystal Field Potential

The Effective Crystal Field Potential PDF Author: J. Mulak
Publisher: Elsevier
ISBN: 0080530710
Category : Science
Languages : en
Pages : 319

Get Book Here

Book Description
As it results from the very nature of things, the spherical symmetry of the surrounding of a site in a crystal lattice or an atom in a molecule can never occur. Therefore, the eigenfunctions and eigenvalues of any bound ion or atom have to differ from those of spherically symmetric respective free ions. In this way, the most simplified concept of the crystal field effect or ligand field effect in the case of individual molecules can be introduced. The conventional notion of the crystal field potential is narrowed to its non-spherical part only through ignoring the dominating spherical part which produces only a uniform energy shift of gravity centres of the free ion terms. It is well understood that the non-spherical part of the effective potential "seen" by open-shell electrons localized on a metal ion plays an essential role in most observed properties. Light adsorption, electron paramagnetic resonance, inelastic neutron scattering and basic characteristics derived from magnetic and thermal measurements, are only examples of a much wider class of experimental results dependent on it. The influence is discerned in all kinds of materials containing unpaired localized electrons: ionic crystals, semiconductors and metallic compounds including materials as intriguing as high-Tc superconductors, or heavy fermion systems. It is evident from the above that we deal with a widespread effect relative to all free ion terms except those which can stand the lowered symmetry, e.g. S-terms. Despite the universality of the phenomenon, the available handbooks on solid state physics pay only marginal attention to it, merely making mention of its occurrence. Present understanding of the origins of the crystal field potential differs essentially from the pioneering electrostatic picture postulated in the twenties. The considerable development of the theory that has been put forward since then can be traced in many regular articles scattered throughout the literature. The last two decades have left their impression as well but, to the authors' best knowledge, this period has not been closed with a more extended review. This has also motivated us to compile the main achievements in the field in the form of a book.

Multiplets of Transition-Metal Ions in Crystals

Multiplets of Transition-Metal Ions in Crystals PDF Author: Satoru Sugano
Publisher: Elsevier
ISBN: 0323154794
Category : Science
Languages : en
Pages : 348

Get Book Here

Book Description
Multiplets of Transition-Metal Ions in Crystals provides information pertinent to ligand field theory. This book discusses the fundamentals of quantum mechanics and the theory of atomic spectra. Comprised of 10 chapters, this book starts with an overview of the qualitative nature of the splitting of the energy level as well as the angular behavior of the wavefunctions. This text then examines the problem of obtaining the energy eigenvalues and eigenstates of the two-electron systems, in which two electrons are accommodated in the t2g and eg shells in a variety of ways. Other chapters discuss the ligand-field potential, which is invariant to any symmetry operation in the group to which symmetry of the system belongs. This book discusses as well the approximate method of expressing molecular orbitals (MO) by a suitable linear combination of atomic orbitals (AO). The final chapter discusses the MO in molecules and the self-consistent field theory of Hartree–Fock. This book is a valuable resource for research physicists, chemists, electronic engineers, and graduate students.

Spectroscopic Methods in Mineralogy

Spectroscopic Methods in Mineralogy PDF Author: A. Beran
Publisher: The Mineralogical Society of Great Britain and Ireland
ISBN: 9634636624
Category : Science
Languages : en
Pages : 676

Get Book Here

Book Description


Wide-Gap Luminescent Materials: Theory and Applications

Wide-Gap Luminescent Materials: Theory and Applications PDF Author: Stanley R. Rotman
Publisher: Springer Science & Business Media
ISBN: 146154100X
Category : Technology & Engineering
Languages : en
Pages : 376

Get Book Here

Book Description
Electro-optic devices based on doped wide-band materials are present in industrial uses, in military applications and in everyday life. Whether one engages in laser surgery with a neodymium-Y AG laser or one communicates overseas using optical fibers, the development of these materials is both scientifically and commercially of great interest. Much of the most innovative work has been done in the last 15 years in this area. A minor revolution in optical fiber communications has occurred with the development of erbium-doped fiber amplifiers. Solid-state laser development shifted into high-gear with the theoretical and experimental study of doubly-doped garnet lasers. Recent developments on semiconductor laser arrays are making diode pumped solid-state lasers commercially feasible. The purpose of this book is to detail these developments and to point out that many of the same underlying physical processes control advances in several diverse applications. For example, the basic science of energy transfer will be discussed by Zharikov et al. and Rotman for energy transfer and dopant-defect interactions, respectively; it will also be crucial in understanding cerium-doped scintilla tors, neodymium-chromium lasers, and up-conversion fiber lasers. As another example, phonon-induced non-radiative relaxation will appear in every chapter in this book.

The Chemistry of the Actinide and Transactinide Elements (3rd ed., Volumes 1-5)

The Chemistry of the Actinide and Transactinide Elements (3rd ed., Volumes 1-5) PDF Author: L.R. Morss
Publisher: Springer Science & Business Media
ISBN: 1402035985
Category : Science
Languages : en
Pages : 4059

Get Book Here

Book Description
The Chemistry of the Actinide and Transactinide Elements is a contemporary and definitive compilation of chemical properties of all of the actinide elements, especially of the technologically important elements uranium and plutonium, as well as the transactinide elements. In addition to the comprehensive treatment of the chemical properties of each element, ion, and compound from atomic number 89 (actinium) through to 109 (meitnerium), this multi-volume work has specialized and definitive chapters on electronic theory, optical and laser fluorescence spectroscopy, X-ray absorption spectroscopy, organoactinide chemistry, thermodynamics, magnetic properties, the metals, coordination chemistry, separations, and trace analysis. Several chapters deal with environmental science, safe handling, and biological interactions of the actinide elements. The Editors invited teams of authors, who are active practitioners and recognized experts in their specialty, to write each chapter and have endeavoured to provide a balanced and insightful treatment of these fascinating elements at the frontier of the periodic table. Because the field has expanded with new spectroscopic techniques and environmental focus, the work encompasses five volumes, each of which groups chapters on related topics. All chapters represent the current state of research in the chemistry of these elements and related fields.

Spectroscopic Properties of Rare Earths in Optical Materials

Spectroscopic Properties of Rare Earths in Optical Materials PDF Author: Guokui Liu
Publisher: Springer Science & Business Media
ISBN: 3540282092
Category : Science
Languages : en
Pages : 567

Get Book Here

Book Description
Aimed at researchers and graduate students, this book provides up-to-date information about the electronic interactions that impact the optical properties of rare earth ions in solids. Its goal is to establish a connection between fundamental principles and the materials properties of rare-earth activated luminescent and laser optical materials. The theoretical survey and introduction to spectroscopic properties covers electronic energy level structure, intensities of optical transitions, ion-phonon interactions, line broadening, and energy transfer and up-conversion. An important aspect of the book lies in its deep and detailed discussions of materials properties and the potential of new applications such as optical storage, information processing, nanophotonics, and molecular probes that have been identified in recent experimental studies. This volume will be a valuable reference book on advanced topics of rare earth spectroscopy and materials science.

Electron Spin Resonance of Paramagnetic Crystals

Electron Spin Resonance of Paramagnetic Crystals PDF Author: L. Sorin
Publisher: Springer Science & Business Media
ISBN: 1461586909
Category : Technology & Engineering
Languages : en
Pages : 268

Get Book Here

Book Description
The authors of this contribution to the literature of resonance spectroscopy in paramagnetic systems are primarily concerned with the properties of the rare earth ions and, as such, the formal derivation of crystal field theory is set out in a manner which reflects this dominant interest. The ions of the 3d transition group are perhaps given too cursory a treatment in Chapter Two for those students of RF spectroscopy who have a somewhat less rare-earth oriented interest in the subject. Since the exam ples cited in the text do include some 3d transition ions, it is perhaps worthwhile in a preface of this sort to extend the broad theoretical concepts and group characteriza tion of Chapter Two to cover, in a somewhat more detailed manner, the derivation of the spin-Hamiltonian for this case. In Chapter Two, mention is made of the fact that for the 4f rare earth ions the spin orbit coupling energy is in general large compared to the crystal field influence of the surrounding ligand matrix. In such a case, the quantum number J is a good quantum number for the rare earth ion in question and the crystal field effects are taken into account within 1M, states. In this formulation, which is pursued in detail in this book, the effects of spin-orbit coupling have been taken care of at the very outset by the d~"ining of the 1M, states.

Optical Properties of 3d-Ions in Crystals

Optical Properties of 3d-Ions in Crystals PDF Author: Nicolae M. Avram
Publisher: Springer Science & Business Media
ISBN: 3642308384
Category : Science
Languages : en
Pages : 278

Get Book Here

Book Description
"Optical Properties of 3d-Ions in Crystals: Spectroscopy and Crystal Field Analysis" discusses spectral, vibronic and magnetic properties of 3d-ions in a wide range of crystals, used as active media for solid state lasers and potential candidates for this role. Crystal field calculations (including first-principles calculations of energy levels and absorption spectra) and their comparison with experimental spectra, the Jahn-Teller effect, analysis of vibronic spectra, materials science applications are systematically presented. The book is intended for researchers and graduate students in crystal spectroscopy, materials science and optical applications. Dr. N.M. Avram is an Emeritus Professor at the Physics Department, West University of Timisoara, Romania; Dr. M.G. Brik is a Professor at the Institute of Physics, University of Tartu, Estonia.

Quantum Theory Of Magnetism, The (2nd Edition)

Quantum Theory Of Magnetism, The (2nd Edition) PDF Author: Norberto Majlis
Publisher: World Scientific Publishing Company
ISBN: 9813106697
Category : Science
Languages : en
Pages : 392

Get Book Here

Book Description
This advanced level textbook is devoted to the description of systems which show ordered magnetic phases. A wide selection of topics is covered, including a detailed treatment of the mean-field approximation as the main paradigm for the phenomenological description of phase transitions. The book discusses the properties of low-dimensional systems and uses Green's functions extensively after a useful mathematical introduction. A thorough presentation of the RKKY and related models of indirect exchange is also featured, and a chapter on surface magnetism, rarely found in other textbooks, adds to the uniqueness of this book.For the second edition, three new chapters have been added, namely on magnetic anisotropy, on coherent magnon states and on local moments. Additionally, the chapter on itinerant magnetism has been enlarged by including a section on paramagnons.

Fundamentals of Magnetism and Spintronics

Fundamentals of Magnetism and Spintronics PDF Author: Atowar Rahman
Publisher: Zorba Books
ISBN: 9393029849
Category : Education
Languages : en
Pages : 442

Get Book Here

Book Description
Fundamentals of Magnetism and Spintronics, develops the idea of magnetism, understand its sources and other related matters step by step. Fundamentals of Magnetism and Spintronics, describes microscopic sources of magnetic field and explains why different bodies behave differently in the presence of an external magnetic field. Different topics in Magnetism and Spintronics have been presented in simple ways using simple mathematics. The objectives are to cover the basic concepts of Magnetism and Spintronics using simple models and to provide coverage of the subject matter as far as possible. Chapters 1 to 3 have been devoted to define the microscopic source of magnetism and to define fundamental parameters of magnetism. Chapter 4 to Chapter 11 have been devoted for the general properties of magnetic materials. There has been tremendous research in the field of material science and magnetism and as a result remarkable success has been achieved in magnetic storage technology. A new subject known as spintronics or magneto-electronics has come up, which is a novel kind of union of elements of material science, magnetism and electrical engineering, with a goal to create devices and architectures for digital electronics applications. Chapter 12 has been devoted to introduce this subject to the students. Simple pictures and heuristic descriptions have been given to introduce basic ideas of spintronics, transport of spin polarized electrons, mechanisms by which several magnetoelectronic devices operate, and basic architectures of MRAM. Contents Chapter 2: Angular momentum 21 Chapter 3: Some definitions 51 Chapter 4: Diamagnetic and Paramagnetic properties of Solids 81 Chapter 5: Magnetism of ordered systems 114 Chapter 6: Spin Waves : Magnons 146 Chapter 7: Magnetic Energies and Magnetic Domains 157 Chapter 8: Magnetic Resonance Phenomena 204 Chapter 9: Magnetism in Thin Films 247 Chapter 10: Some Magnetic Phenomena 259 Chapter 11: Magnetic measurements 286 Chapter 12: Fundamentals of Spintronics 299 Problems 357 References 373