The Jahn-Teller Effect and Vibronic Interactions in Modern Chemistry


Book Description

The first half of the title of this book may delude the uninitiated reader. The term '"Jahn-Teller effect," taken literally, refers to a special effect inherent in particular molecular systems. Actually, this term implies a new approach to the general problem of correlations between the structure and properties of any molecular polyatomic system, including solids. Just such a new approach, or concept (in some sense, a new outlook or even a new way of thinking), which leads not to one special effect but to a series of different effects and laws, is embodied in the many ( ~ 4000) studies devoted to the investigation and application of the Jahn-Teller effect. The term "vibronic interactions" seems to be most appropriate to the new concept, and this explains the origin of the second half of the title. The primary objective of this book is to present a systematic develop ment of the concept of vibronic interactions and its applications, and to illustrate its possibilities and significance in modern chemistry. In the first three chapters (covering about one-third of the book) the theoretical background of the vibronic concept and Jahn-Teller effect is given. The basic ideas are illustrated fully, although a comprehensive presentation of the theory with all related mathematical deductions is beyond the scope of this book. In the last three chapters the applications of theory to spectro scopy, stereochemistry and crystal chemistry, reactivity, and catalysis, are illustrated by a series of effects and laws.




The Jahn-Teller Effect


Book Description

The Jahn-Teller effect continues to be a paradigm for structural instabilities and molecular dynamical processes. This volume provides a survey of the current Jahn-Teller interactions at the interface of quantum chemistry and condensed matter physics.




A Textbook of Inorganic Chemistry – Volume 1


Book Description

An advanced-level textbook of inorganic chemistry for the graduate (B.Sc) and postgraduate (M.Sc) students of Indian and foreign universities. This book is a part of four volume series, entitled "A Textbook of Inorganic Chemistry – Volume I, II, III, IV". CONTENTS: Chapter 1. Stereochemistry and Bonding in Main Group Compounds: VSEPR theory; dπ -pπ bonds; Bent rule and energetic of hybridization. Chapter 2. Metal-Ligand Equilibria in Solution: Stepwise and overall formation constants and their interactions; Trends in stepwise constants; Factors affecting stability of metal complexes with reference to the nature of metal ion and ligand; Chelate effect and its thermodynamic origin; Determination of binary formation constants by pH-metry and spectrophotometry. Chapter 3. Reaction Mechanism of Transition Metal Complexes – I: Inert and labile complexes; Mechanisms for ligand replacement reactions; Formation of complexes from aquo ions; Ligand displacement reactions in octahedral complexes- acid hydrolysis, base hydrolysis; Racemization of tris chelate complexes; Electrophilic attack on ligands. Chapter 4. Reaction Mechanism of Transition Metal Complexes – II: Mechanism of ligand displacement reactions in square planar complexes; The trans effect; Theories of trans effect; Mechanism of electron transfer reactions – types; outer sphere electron transfer mechanism and inner sphere electron transfer mechanism; Electron exchange. Chapter 5. Isopoly and Heteropoly Acids and Salts: Isopoly and Heteropoly acids and salts of Mo and W: structures of isopoly and heteropoly anions. Chapter 6. Crystal Structures: Structures of some binary and ternary compounds such as fluorite, antifluorite, rutile, antirutile, crystobalite, layer lattices- CdI2, BiI3; ReO3, Mn2O3, corundum, pervoskite, Ilmenite and Calcite. Chapter 7. Metal-Ligand Bonding: Limitation of crystal field theory; Molecular orbital theory: octahedral, tetrahedral or square planar complexes; π-bonding and molecular orbital theory. Chapter 8. Electronic Spectra of Transition Metal Complexes: Spectroscopic ground states, Correlation and spin-orbit coupling in free ions for Ist series of transition metals; Orgel and Tanabe-Sugano diagrams for transition metal complexes (d1 – d9 states); Calculation of Dq, B and β parameters; Effect of distortion on the d-orbital energy levels; Structural evidence from electronic spectrum; John-Tellar effect; Spectrochemical and nephalauxetic series; Charge transfer spectra; Electronic spectra of molecular addition compounds. Chapter 9. Magantic Properties of Transition Metal Complexes: Elementary theory of magneto - chemistry; Guoy’s method for determination of magnetic susceptibility; Calculation of magnetic moments; Magnetic properties of free ions; Orbital contribution, effect of ligand-field; Application of magneto-chemistry in structure determination; Magnetic exchange coupling and spin state cross over. Chapter 10. Metal Clusters: Structure and bonding in higher boranes; Wade’s rules; Carboranes; Metal carbonyl clusters - low nuclearity carbonyl clusters; Total electron count (TEC). Chapter 11. Metal-π Complexes: Metal carbonyls: structure and bonding; Vibrational spectra of metal carbonyls for bonding and structure elucidation; Important reactions of metal carbonyls; Preparation, bonding, structure and important reactions of transition metal nitrosyl, dinitrogen and dioxygen complexes; Tertiary phosphine as ligand.







Vibronic Processes in Inorganic Chemistry


Book Description

This volume reports the main lectures and seminars given at the NATO Advanced Study Institute on Vibronic Processes in Inorganic Chemistry held at Riva del Sole, Tuscany, Italy between 7th and 18th September 1988. In addition to the about 40 hours of lectures repres ented by this volume, a further fifteen lectures on current research topics were given by the other participants. Many factors contributed to the decision to hold this ASI but the final trigger was given at a meeeting in Padova when Marco Bettinelli, Lorenzo Disipio and Gianluigi Ingletto asked me to recommend a text where the diverse conceptual, spectroscopic and structural consequences of the impossibility of treating the motions of the electrons and nuclei independantly in inorganic compounds were presented. There seemed to be no suitable comprehensive text where the relationship between the relatively simple theoretical ideas and the huge range of their application in inorganic chemistry and physics was developed. The Institute and this text are a contribution to filling this gap. Seventy-nine participants from fifteen countries attended the Institute. Topics raised in the lectures and from the participants own research frequently led to discussions which went on long into the night.




Advances in Chemical Physics, Volume 160


Book Description

The Advances in Chemical Physics series provides the chemical physics field with a forum for critical, authoritative evaluations of advances in every area of the discipline. This volume explores the following topics: Thermodynamic Perturbation Theory for Associating Molecules Path Integrals and Effective Potentials in the Study of Monatomic Fluids at Equilibrium Sponteneous Symmetry Breaking in Matter Induced by Degeneracies and Pseudogeneracies Mean-Field Electrostatics Beyond the Point-Charge Description First Passage Processes in Cellular Biology Theoretical Modeling of Vibrational Spectra and Proton Tunneling in Hydroen-Bonded Systems




The Theory of the Jahn-Teller Effect


Book Description

This book provides a comprehensive discussion of the Jahn-Teller Effect (JTE), focusing on the boson-fermion interaction. While current research is concerned with measuring and calculating ever more sophisticated and complex manifestations of the JT effect, the present volume takes away the epicycles of the theory and focuses on the symmetry dilemma at its core. When fermions and bosons meet, they get entangled and form a new dynamic reality. According to the rules of Molecular Symmetry, this reality is limited to a small set of patterns, with degeneracy cardinalities: 2, 3, 4, 5, and 6. The novelty of the book is that it adopts a unique mathematical technique, known as the Bargmann-Fock representation, and treats all degeneracies in detail. So far, this method was only applied to the simplest doublet case therefore its extension to the entire range of cases offers a new unified perspective. This volume will help the reader acquire a clear understanding of the JT effect, discover its universal mechanism and it will be a great tool for researchers and graduates working on this topic.




Vibronic Interactions in Molecules and Crystals


Book Description

Vibronic interaction effects constitute a new field of investigation in the physics and chemistry of molecules and crystals that combines all the phenomena and laws originating from the mixing of different electronic states by nuclear displacements. This field is based on a new concept which goes beyond the separate descriptions of electronic and nuclear motions in the adiabatic approximation. Publications on this topic often appear under the title of the lahn-Thller effect, although the area of application of the new approach is much wider: the term vibronic interaction seems to be more appropriate to the field as a whole. The present understanding of the subject was reached only recently, during the last quarter of a century. As a result of intensive development of the theory and experiment, it was shown that the nonadiabatic mixing of close-in-energy elec tronic states under nuclear displacements and the back influence of the modified electronic structure on the nuclear dynamics result in a series of new effects in the properties of molecules and crystals. The applications of the theory of vibronic in of spectroscopy [including visible, ultraviolet, in teractions cover the full range frared, Raman, EPR, NMR, nuclear quadrupole resonance (NQR), nuclear gam ma resonance (NOR), photoelectron and x-ray spectroscopy], polarizability and magnetic susceptibility, scattering phenomena, ideal and impurity crystal physics and chemistry (including structural as well as ferroelectric phase transitions), stereochemistry and instability of molecular (including biological) systems, mechanisms of chemical reactions and catalysis.