Electronic And Nuclear Dynamics In Molecular Systems

In recent years, there has been rapid growth in the research field of real-time observation of nuclear and electronic dynamics in molecules. Its time range extends from femtoseconds to attoseconds. This has been made possible by the development of both laser technology and time-dependent theoretical treatments. Indeed, this research field is arguably the most active one in molecular science, second only to femtosecond chemistry. The outcome of the research is expected to make an important contribution to physics, materials science and biology as well as chemistry. In this monograph, the fundamental theories and methods, as well as experimental methods and results, of real-time observation of both nuclear and electronic motions in molecular systems are described. It is suitable for researchers who want to make an active contribution to the new research field and for graduate students who are interested in ultra-fast nuclear and electron dynamics in molecular systems.

Charge and Energy Transfer Dynamics in Molecular Systems Comprehensive resource offering knowledge on charge and energy transfer dynamics in molecular systems and nanostructures Charge and Energy Transfer Dynamics in Molecular Systems provides a unified description of different charge and energy transfer phenomena in molecular systems with emphasis on the theory, bridging the regimes of coherent and dissipative dynamics and thus presenting classic rate theories as well as modern treatments of ultrafast phenomena. Starting from microscopic models, the common features of the different transfer processes are highlighted, along with applications ranging from vibrational energy flow in large polyatomic molecules, the motion of protons in solution, up to the concerted dynamics of electronic and nuclear degrees of freedom in molecules and molecular aggregates. The newly revised and updated Fourth Edition contains a more detailed coverage of recent developments in density matrix theory, mixed quantum-classical methods for dynamics simulations, and a substantially expanded treatment of time-resolved spectroscopy. The book is written in an easy-to-follow style, including detailed mathematical derivations, thus making even complex concepts understandable and applicable. Charge and Energy Transfer Dynamics in Molecular Systems includes information on: Electronic and vibrational molecular states, covering molecular Schrödinger equation, Born—Oppenheimer separation and approximation, Hartree-Fock equations and other electronic structure methods Dynamics of isolated and open quantum systems, covering multidimensional wave packet dynamics, and different variants of density operator equations Interaction of molecular systems with radiation fields, covering linear and nonlinear optical response using the correlation function approach Intramolecular electronic transitions, covering optical transition and internal conversion processes Transfer processes of electrons, protons, and electronic excitation energy Providing in-depth coverage of the subject, Charge and Energy Transfer Dynamics in Molecular Systems is an essential resource for anyone working on timely problems of energy and charge transfer in physics, chemistry and biophysics as well as for all engaged in nanoscience and organic electronics.

This volume aims at a comprehensive introduction into the theory of nonadiabatic molecular processes an increasingly relevant and rapidly expanding segment of molecular quantum dynamics. This very active and current field of research deals with molecular interactions involving transitions between electronic states, which occur typically in cases of reactive scattering between molecules, photoexcitation or strong vibronic and rotational coupling between electronic and nuclear degrees of freedom. The main objective of Electron Dynamics in Molecular Interactions is to provide a synoptic presentation of some very recent theoretical efforts and to contrast them with the more traditional models of nonadiabatic molecular processes. In these presented models derived from their quantum dynamical fundaments, their interrelations are discussed, and their characteristic applications to concrete chemical systems are also outlined. This volume also includes an assessment of the present status of electron dynamics and a report on novel developments to meet the current challenges in the field. There is a need for a systematic comparative treatise as nonadiabatic theories, which are of considerably higher complexity than the more traditional adiabatic approaches, are steadily gaining in importance. This volume addresses a broad readership ranging from physics or chemistry graduate students to specialists in the field of theoretical quantum dynamics.

Providing a unified description of different transfer phenomena in molecular systems, this volume serves as an introduction for graduate students and researchers. The authors manage to bridge the regimes of coherent and dissipative dynamics and thus establish the connection between classic rate theories and modern treatments of ultrafast phenomena. Starting from microscopic models, the common features of the different transfer processes are highlighted. The applications range from vibrational energy flow in large polyatomics, the motion of protons in solution, up to the concerted dynamics of electronic and nuclear degrees of freedom in molecules and molecular aggregates.

This unique volume offers a clear perspective of the relevant methodology relating to the chemical theory of the next generation beyond the Born-Oppenheimer paradigm. It bridges the gap between cutting-edge technology of attosecond laser science and the theory of chemical reactivity. The essence of this book lies in the method of nonadiabatic electron wavepacket dynamic, which will set a new foundation for theoretical chemistry. In light of the great progress of molecular electronic structure theory (quantum chemistry), the authors show a new direction towards nonadiabatic electron dynamics, in which quantum wavepackets have been theoretically and experimentally revealed to bifurcate into pieces due to the strong kinematic interactions between electrons and nuclei. The applications range from nonadiabatic chemical reactions in photochemical dynamics to chemistry in densely quasi-degenerated electronic states that largely fluctuate through their mutual nonadiabatic couplings. The latter is termed as “chemistry without the potential energy surfaces” and thereby virtually no theoretical approach has been made yet. Restarting from such a novel foundation of theoretical chemistry, the authors cast new light even on the traditional chemical notions such as the Pauling resonance theory, proton transfer, singlet biradical reactions, and so on. Contents:The Aim of This Book: Where are We?Basic Framework of Theoretical ChemistryNuclear Dynamics on Adiabatic Electronic Potential Energy SurfacesBreakdown of the Born–Oppenheimer Approximation: Classic Theories of Nonadiabatic Transitions and Ideas BehindDirect Observation of the Wavepacket Bifurcation Due to Nonadiabatic TransitionsNonadiabatic Electron Wavepacket Dynamics in Path-branching RepresentationDynamical Electron Theory for Chemical ReactionsMolecular Electron Dynamics in Laser Fields Readership: Graduate students, professional scientists in theoretical chemistry, quantum chemistry, chemical dynamics, nonadiabatic transition, molecular physics, electron dynamics, and experimentalists in laser chemistry (including ultrafast chemical dynamics), photochemistry, laser control of chemical reactions, and scientists working in physical chemistry and chemical physics in general. Key Features:Presents a new framework of theory for ultrafast chemical reactions based on the nonadiabatic electron wavepacket dynamicsOffers a very powerful yet futuristic methodology to handle the attosecond electron-wavepacket quantum dynamics associated with non-Born-Oppenheimer nuclear pathsDescribes the original and powerful practices to cope with actual molecular systems that have been attained through authors' long-standing studiesKeywords:Electron Dynamics;Laser Chemistry;Nonadiabatic Transitions;Quantum Wave Packet;Ultrafast Chemical Dynamics;Attosecond Dynamics;Control Of Chemical Reactions;Photodynamics;Avoided Crossing;Conical Intersection;Pump-Probe;Photoelectron Spectroscopy;Excited State Chemistry;Semiclassical Theory

This volume is the first of a set of two which contain the invited lectures given at the international seminar of the same title held at the Centre de Mecanique Ondulatoire Appliquee du Centre National de la Recherche Scientifique in Paris (France) from October 1983 to May 1985. They are intended to provide a survey of topics of current interest relative to the structure and the dynamics of molecular systems. The papers have been selected on the basis of their relevance to the following four topics: i) molecular conformations and transformations; ii) molecular relaxation and motion; iii) charge, spin and momentum distributions in molecular solids; iv) collective phenomena in condensed matter. The first volume deals f)1ostly with the first two topics, the second volume mostly with the last two. Each volume consists of about fifteen self contained, reference contributions covering recent achievements in active branches of molecular physics and physical chemistry. The first four papers of the present volume deal with theoretical aspects of structure and reactivity problems, with particular attention being paid to topology considerations, which have joined symmetry con siderations as an important tool in approaching chemistry problems. The treatment of nuclear probability density distributions is performed on a model basis for a simple system, even though it has come to the attention of theoreticians through experimental results for complex systems.