Physics and Chemistry of Materials with Relaxation Processes in Molecular Excited States Book 2 (Paperback)

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.