This work deals with J-aggregates, which have a long history of research. The volume covers electronic states, linear and nonlinear optical properties. Various properties and processes of J- aggregates, such as super-radiance, excitons, photon echo, geometrical structure, electron transfer and femtosecond spectroscopy, are discussed.

Living things use solar energy in two ways: in the transmission of information and in the conversion of light energy to chemical energy. In order to elucidate the molecular mechanisms of highly sensitive visual responses and other photosensitive responses of biological systems, and the very efficient transduction of photoenergy to chemical energy in photosynthesis, it is important to observe molecular processes in biological systems. Using highly developed laser spectroscopic techniques, great progress has recently been achieved in the area of various primary processes in photobiology. It was...