Dynamics of Molecular Excitons provides a comprehensive, but concise description of major theories on the dynamics of molecular excitons, intended to serve as a self-contained resource on the topic. Designed to help those new to this area gain proficiency in this field, experts will also find the book useful in developing a deeper understanding of the subject. The starting point of the book is the standard microscopic definition of molecular Hamiltonians presented in commonly accepted modern quantum mechanical notations. Major assumptions and approximations involved in constructing Frenkel-type exciton Hamiltonians, which are well established, but are often hidden under arcane notations and approximations of old publications, are presented in detail. This will help quantum chemists understand the major assumptions involved in the definition of commonly used exciton models. Rate theories of exciton dynamics, such as Förster and Dexter theories and their modern generalizations, are presented in a unified and detailed manner. In addition, important aspects that are often neglected, such as local field effect and the role of fluctuating environments, are discussed. Various quantum dynamics methods allowing coherent dynamics of excitons are presented in a systematic manner in the context of quantum master equations or path integral formalisms. The author also provides a detailed theoretical explanation for the major spectroscopic techniques probing exciton dynamics, including modern two-dimensional electronic spectroscopy, with a critical assessment of the implications of these spectroscopic measurements. Finally, the book includes a brief overview of major applications including an explanation of organic photovoltaic materials and natural light harvesting complexes. - Covers major theories of exciton dynamics in a consciously concise and easily readable way - Bridges the gap between quantum dynamics working with phenomenological exciton Hamiltonian and quantum chemistry construct reliable models amenable for dynamics calculations from ab initio calculations - Explores modern nonlinear electronic spectroscopy techniques to probe exciton dynamics, showing how it is applied

Applying a unified quantum approach, contributors offer fresh insights into the theoretical developments in the excitation energy transfer processes in condensed matter. This comprehensive volume examines Frenkel and Wannier excitonic processes; rates of excitonic processes; theory of laser sputter and polymer ablation; and polarons, excitonic polarons and self-trapping.

Low-temperature spectroscopy of organic molecular crystals came into being in the late 20s, just when quantum physics of solids as a whole began to de velop vigorously. Already in the early works, two experimental facts of prime importance were discovered: the presence of a multitude of narrow bands in the low-temperature spectrum of a crystal, and a close relationship between the spectrum of the crystal and that of the constituent molecules. These findings immediately preceded the celebrated paper of Frenkel in which he went beyond the framework of Bloch's scheme and advanced the exciton concept. Subsequent investigations showed that the most interesting features of the spectra of molecular crystals are associated with excitons, and then the spectroscopy of molecular excitons began to form gradually on the basis of the spectroscopy of organic crystals. The molecular exciton became synonymous to the Frenkel exciton in a molecular crystal. In view of the difficulties involved in the analysis of rich spectra con taining many tens of bands, the spectroscopy of molecular crystals had long been connected most closely with the spectroscopy of molecules. It had deve loped independently, to a large extent, from the other branches of solid state physics. This was also emphasized by the difference in experimental techniques, the specific properties of the objects, etc. As a result, there was some lag in ideas and concepts.