Transition metal and rare earth compounds are investigated intensively because of important questions concerning fundamental research problems. More recently also their enormous potential for the development of new materials for photophysical and photochemical applications has been explored. Thus, it is important to focus on a deeper understanding of the elctronic energies, transition prohabilities, intermolecular interactions, etc.. This task has been accomplished by leading researchers in the field. They present introductions into, but also detailed reviews of the current state of knowledge...

For a long time, the properties of transition metal and rare earth compounds have fascinated chemists and physicists from a scientific view-point, and more recently also their enormous potential as new materials has been explored. Applications in different fields have already been realized or are under c- rent investigation, for example, new laser materials, IR to visible upconversion systems, compounds for photolithographic processes, systems involving pho- redox processes for solar energy conversion, new photovoltaic devices, chemical sensors, biosensors, electroluminescent devices (OLEDs)...