Relaxation Processes in Molecular Excited States

Relaxation Processes in Molecular Excited States PDF

Author: J. Fünfschilling

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 282

ISBN-13: 9400908636

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Relaxation phenomena of excited molecular states are abundant in all nature. They mediate such key processes as photochemical reactions or even the pathways of ordinary chemical reactions. However, for a long time the main research in electronic relaxation processes was concerned with anorganic solids, in part because of their great technological importance (photography, semiconductors ... ) in part also because these compounds were the "workhorses" of the solid state physicists. In the last 30 years, there was a steadily increasing interest in organic molecular systems, first in molecular crystals and later in all forms of molecular solids (glasses, polymers, membranes, ... ). The present volume combines papers on quite different types of relaxation phenomena: the type of solid studied, the electronic states involved, the physical processes responsible for the relaxations are all different. Nevertheless, after reading this book, a more clear and complete picture of the phenomenon "relaxa tion" emerges that proves that this volume is more than just a collection of individual articles. The volume starts with the paper "Spin-lattice and spin-spin relaxation in photo-excited triplet states in molecular crystals" by Jan Schmidt. Even in these seemingly simple systems of isolated guest molecules in a single crystal host, the relaxation phenomena are quite involved and a very thorough investigation is necessary to find the key relaxation processes. The end of the article provides a bridge to the following paper: it treats interactions of two molecules (dimers), where resonant interactions become important and lead to new, characteristic relaxation processes.

Electron Spin Relaxation in Liquids

Electron Spin Relaxation in Liquids PDF

Author: L. Muus

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 543

ISBN-13: 146158678X

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Electron spin relaxation has established itself as an important experimental method for studying the details of molecular motion in liquids, and as a harsh testing ground for theoreticians. The theo retical difficulties are connected with the complexity of the mole cular motion, and the theoretical interest lies not only in its im portant consequences for the interpretation of experiments, but also in the fascination of a system in which a well-defined quantum me chanical component is in interaction with a complex quasi-classical environment. It is because the theories are concerned with such dissimilar but connected systems that the techniques involved are so numerous. Many of the standard manipulations of quantum mechanics must be brought to bear, and at the same time they must be combined with statistical techniques which are often of considerable sophis tication. The purpose of this volume is to present a survey of these techniques and their application to spin relaxation problems. No single volume can be exhaustive, but we believe that the contri butions to this volume are sufficiently broad to show how those who are concerned with spin relaxation problems think about the subject and circumvent, or expose, its difficulties. The first few Chapters (I-V) review the basic quantum mechani cal and statistical manipulations which are often used.

Relaxation Phenomena

Relaxation Phenomena PDF

Author: Wolfgang Haase

Publisher: Springer Science & Business Media

Published: 2013-03-09

Total Pages: 732

ISBN-13: 3662097478

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The authors describe the electric, magnetic and other relaxational processes in a wide spectrum of materials: liquid crystals, molecular magnets, polymers, high-Tc superconductors and glasses. The book summarizes the phenomenological fundamentals and the experimental methods used. A detailed description of molecular and collective dynamics in the broad range of liquid crystals is presented. Magnetic systems, high-Tc superconductors, polymers and glasses are an important subject of matter. It is shown that the researchers working on relaxation processes in different fields of materials sciences are dealing with the same physical fundamentals, but are sometimes using slightly different terms. The book is addressed to scientists, engineers, graduate and undergraduate students, experimentalists and theorists in physics, chemistry, materials sciences and electronic engineering. Many internationally well known experts contribute to it.

Electron Spin Resonance and Related Phenomena in Low-Dimensional Structures

Electron Spin Resonance and Related Phenomena in Low-Dimensional Structures PDF

Author: Marco Fanciulli

Publisher: Springer Science & Business Media

Published: 2009-08-24

Total Pages: 272

ISBN-13: 3540793658

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Here is a discussion of the state of the art of spin resonance in low dimensional structures, such as two-dimensional electron systems, quantum wires, and quantum dots. Leading scientists report on recent advances and discuss open issues and perspectives.

Phonon Scattering in Solids

Phonon Scattering in Solids PDF

Author: L. Challis

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 459

ISBN-13: 1461342716

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The Second International Conference on Phonon Scattering in Solids was held at the University of Nottingham from August 27th - 30th 1975. It was attended by 192 delegates from 24 countries who were accompanied by 43 members of their families. Eleven invited papers were read and 96 contributed papers; the contributed papers were in two parallel sessions. The Conference included the topics of the two International Conferences held in France in 1972, in Paris and at Ste Maxime. The Conference brought together workers concerned with many aspects of phonon scattering in solids and liquid helium. Some of the work reported were studies of the intrinsic properties of diel ectric materials such as the effects of anharmonicity, dispersion and anisotropy on phonon propagation and the conditions for the existence of zero sound and second sound modes. Work was also pres ented on various aspects of phonon interaction with free electrons in metals and semiconductors. A substantial part of the Conference was devoted to phonon spectroscopy - investigations of the energy levels of ions or neutral impurities by observing the resonant absorp tion or scattering of phonons. The materials being studied include paramagnetic and parae1ectric solids, amorphous systems in which the 'impurities' appear to be intrinsic, and semiconductors. Work was reported on the use of phonons to observe phase transitions; in some cases the cooperative phase also arises through strong spin phonon coupling. One of the intriguing unsolved problems discussed in detail at the Conference is the Kapitza conductance problem.

Relaxation in Magnetic Resonance

Relaxation in Magnetic Resonance PDF

Author: Charles P. Jr. Poole

Publisher: Elsevier

Published: 2012-12-02

Total Pages: 409

ISBN-13: 0323151825

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Relaxation in Magnetic Resonance contains a series of lecture notes for a special topics course at the University of South Carolina in 1967. This book contains 21 chapters that summarize the main theoretical formulations and experimental results of magnetic resonance relaxation phenomena in several physical systems. This text deals first with the various methods in determining the relaxation behavior of the macroscopic spin system, such as Bloch equations, saturation methods, and transient resonant absorption. The subsequent chapters discuss the homogeneous and inhomogeneous resonant lines in solids and liquids and the significance of the Kubo-Tomita and Redfield theories in magnetic resonance. This book then considers the background research on electron spin resonance and relaxation in ionic solids. The concluding chapters explore the acoustic absorption coefficient and dielectric constant calculation; the relaxation processes in paramagnetic substance; and the characteristics of Mössbauer spectra and their application in magnetic relaxation. This book will be useful to both graduate students embarking upon thesis problems in relaxation and more advanced workers who seek an overall summary of the status of the field, as well as to physicists and chemists.

Electron Spin Interactions in Chemistry and Biology

Electron Spin Interactions in Chemistry and Biology PDF

Author: Gertz Likhtenshtein

Publisher: Springer

Published: 2016-07-25

Total Pages: 355

ISBN-13: 3319339273

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This book presents the versatile and pivotal role of electron spin interactions in nature. It provides the background, methodologies and tools for basic areas related to spin interactions, such as spin chemistry and biology, electron transfer, light energy conversion, photochemistry, radical reactions, magneto-chemistry and magneto-biology. The book also includes an overview of designing advanced magnetic materials, optical and spintronic devices and photo catalysts. This monograph will be of interest to scientists and graduate students working in the areas related to spin interactions physics, biophysics, chemistry and chemical engineering.