This volume reports the main lectures and seminars given at the NATO Advanced Study Institute on Vibronic Processes in Inorganic Chemistry held at Riva del Sole, Tuscany, Italy between 7th and 18th September 1988. In addition to the about 40 hours of lectures repres­ ented by this volume, a further fifteen lectures on current research topics were given by the other participants. Many factors contributed to the decision to hold this ASI but the final trigger was given at a meeeting in Padova when Marco Bettinelli, Lorenzo Disipio and Gianluigi Ingletto asked me to recommend a text where the diverse conceptual, spectroscopic and structural consequences of the impossibility of treating the motions of the electrons and nuclei independantly in inorganic compounds were presented. There seemed to be no suitable comprehensive text where the relationship between the relatively simple theoretical ideas and the huge range of their application in inorganic chemistry and physics was developed. The Institute and this text are a contribution to filling this gap. Seventy-nine participants from fifteen countries attended the Institute. Topics raised in the lectures and from the participants own research frequently led to discussions which went on long into the night.

Overture: Introducing Vibronic Couplings.- Vibronic Coupling, Bases.- Vibrations of Crystal Lattices.- A Plain Introduction to Jahn-Teller Couplings.- The Theory of the Jahn-Teller Effect.- Vibronic Intensities.- Electronic Spectroscopy.- The General Theory of Radiative and Non Radiative Transitions in Centrosymmetric Coordination Compounds of the Transition Metal Ions.- Electronic and Vibronic Structures of Single-Crystal [Ru(bpy)3](PF6)2 and Doped [Os(bpy)3]2+.- Orbital Models and the Photochemistry of Transition-Metal Complexes.- Two-Photon Spectroscopy of the 4A2g ? 4T2g Transition in Mn4+ Impurity Ions in Crystals.- The Jahn-Teller Effect in Cu2+ in Six-, Five- and Four-Coordination. Examples for the Importance of Vibronic Interactions in Transition Metal Chemistry.- Cooperative Vibronic Effects: Electron Transfer in Solution and the Solid State.- Raman, Resonance Raman and Electronic Raman Spectroscopy.- The Ligand Polarisation Model for d-d and f-f Intensities.- Non-Resonant Energy Transfer between Inorganic Ions in Solids.- Vibronic Interactions in the Electronic Ground State: Vibrational Circular Dichroism Spectroscopy.