Quantum phenomena are ubiquitous in complex molecular systems - as revealed by many experimental observations based upon ultrafast spectroscopic techniques - and yet remain a challenge for theoretical analysis. The present volume, based on a May 2005 workshop, examines and reviews the state-of-the-art in the development of new theoretical and computational methods to interpret the observed phenomena. Emphasis is on complex molecular processes involving surfaces, clusters, solute-solvent systems, materials, and biological systems. The research summarized in this book shows that much can be done to explain phenomena in systems excited by light or through atomic interactions. It demonstrates how to tackle the multidimensional dynamics arising from the atomic structure of a complex system, and addresses phenomena in condensed phases as well as phenomena at surfaces. The chapters on new methodological developments cover both phenomena in isolated systems, and phenomena which involve the statistical effects of an environment, such as fluctuations and dissipation. The methodology part explores new rigorous ways to formulate mixed quantum-classical dynamics in many dimensions, along with new ways to solve a many-atom Schroedinger equation, or the Liouville-von Neumann equation for the density operator, using trajectories and ideas related to hydrodynamics. Part I treats applications to complex molecular systems, and Part II covers new theoretical and computational methods

The role of quantum coherence in promoting the e ciency of the initial stages of photosynthesis is an open and intriguing question. Lee, Cheng, and Fleming, Science 316, 1462 (2007) The understanding and design of functional biomaterials is one of today's grand challenge areas that has sparked an intense exchange between biology, materials sciences, electronics, and various other disciplines. Many new - velopments are underway in organic photovoltaics, molecular electronics, and biomimetic research involving, e. g. , arti cal light-harvesting systems inspired by photosynthesis, along with a host of other concepts and device applications. In fact, materials scientists may well be advised to take advantage of Nature's 3. 8 billion year head-start in designing new materials for light-harvesting and electro-optical applications. Since many of these developments reach into the molecular domain, the - derstanding of nano-structured functional materials equally necessitates f- damental aspects of molecular physics, chemistry, and biology. The elementary energy and charge transfer processes bear much similarity to the molecular phenomena that have been revealed in unprecedented detail by ultrafast op- cal spectroscopies. Indeed, these spectroscopies, which were initially developed and applied for the study of small molecular species, have already evolved into an invaluable tool to monitor ultrafast dynamics in complex biological and materials systems. The molecular-level phenomena in question are often of intrinsically quantum mechanical character, and involve tunneling, non-Born- Oppenheimer e ects, and quantum-mechanical phase coherence.

Ultrafast Dynamics at the Nanoscale provides a combined experimental and theoretical insight into the molecular-level investigation of light-induced quantum processes in biological systems and nanostructured (bio)assemblies. Topics include DNA photostability and repair, photoactive proteins, biological and artificial light-harvesting systems, plasmonic nanostructures, and organic photovoltaic materials, whose common denominator is the key importance of ultrafast quantum effects at the border between the molecular scale and the nanoscale. The functionality and control of these systems have been under intense investigation in recent years in view of developing a detailed understanding of ultrafast nanoscale energy and charge transfer, as well as fostering novel technologies based on sustainable energy resources. Both experiment and theory have made big strides toward meeting the challenge of these truly complex systems. This book, thus, introduces the reader to cutting-edge developments in ultrafast nonlinear optical spectroscopies and the quantum dynamical simulation of the observed dynamics, including direct simulations of two-dimensional optical experiments. Taken together, these techniques attempt to elucidate whether the quantum coherent nature of ultrafast events enhances the efficiency of the relevant processes and where the quantum-classical boundary sets in, in these high-dimensional biological and material systems. The chapters contain well-illustrated accounts of the authors' research work, including didactic introductory material, and address a multidisciplinary audience from chemistry, physics, biology, and materials sciences. The book is, therefore, a must-have for graduate- and postgraduate-level researchers who wish to learn about molecular nanoscience from a combined spectroscopic and theoretical viewpoint.

Quantum phenomena are ubiquitous in complex molecular systems - as revealed by many experimental observations based upon ultrafast spectroscopic techniques - and yet remain a challenge for theoretical analysis. The present volume, based on a May 2005 workshop, examines and reviews the state-of-the-art in the development of new theoretical and computational methods to interpret the observed phenomena. Emphasis is on complex molecular processes involving surfaces, clusters, solute-solvent systems, materials, and biological systems. The research summarized in this book shows that much can be done to explain phenomena in systems excited by light or through atomic interactions. It demonstrates how to tackle the multidimensional dynamics arising from the atomic structure of a complex system, and addresses phenomena in condensed phases as well as phenomena at surfaces. The chapters on new methodological developments cover both phenomena in isolated systems, and phenomena which involve the statistical effects of an environment, such as fluctuations and dissipation. The methodology part explores new rigorous ways to formulate mixed quantum-classical dynamics in many dimensions, along with new ways to solve a many-atom Schroedinger equation, or the Liouville-von Neumann equation for the density operator, using trajectories and ideas related to hydrodynamics. Part I treats applications to complex molecular systems, and Part II covers new theoretical and computational methods

The role of quantum coherence in promoting the e ciency of the initial stages of photosynthesis is an open and intriguing question. Lee, Cheng, and Fleming, Science 316, 1462 (2007) The understanding and design of functional biomaterials is one of today's grand challenge areas that has sparked an intense exchange between biology, materials sciences, electronics, and various other disciplines. Many new - velopments are underway in organic photovoltaics, molecular electronics, and biomimetic research involving, e. g. , arti cal light-harvesting systems inspired by photosynthesis, along with a host of other concepts and device applications. In fact, materials scientists may well be advised to take advantage of Nature's 3. 8 billion year head-start in designing new materials for light-harvesting and electro-optical applications. Since many of these developments reach into the molecular domain, the - derstanding of nano-structured functional materials equally necessitates f- damental aspects of molecular physics, chemistry, and biology. The elementary energy and charge transfer processes bear much similarity to the molecular phenomena that have been revealed in unprecedented detail by ultrafast op- cal spectroscopies. Indeed, these spectroscopies, which were initially developed and applied for the study of small molecular species, have already evolved into an invaluable tool to monitor ultrafast dynamics in complex biological and materials systems. The molecular-level phenomena in question are often of intrinsically quantum mechanical character, and involve tunneling, non-Born- Oppenheimer e ects, and quantum-mechanical phase coherence.