Molecular Spectroscopy–XI provides information pertinent to the fundamental aspects of molecular spectroscopy. This book discusses the modifications of molecular spectra when the density varies as a function of temperature and pressure. Organized into 15 chapters, this book begins with an overview of the several processes concerning triplet excitons leading to magnetic-field sensitive luminescence in organic crystals and related compounds. This text then examines the methods of investigation of the exciton band structures in molecular crystals. Other chapters consider the conditions for the equivalence of Fourier spectroscopy and of slow passage experiments in nuclear magnetic resonance. This book discusses as well the application of computer technology in carbon-13 magnetic resonance spectroscopy. The final chapter deals with the application of high-resolution proton and carbon-13 n.m.r. spectroscopy for the investigation of the molecular conformations in proteins. This book is a valuable resource for organic chemists, biologists, microbiologists, scientists, and research workers.