Infrared-laser-induced unimolecular reactions

Abstract
Photochemistry, which deals with the way in which chemical reactions are induced or altered by the presence of photons, has been a very active branch of science for many years. Although visible and ultraviolet photons, by giving rise to excited electronic states, have the most pronounced effects, much attention in recent years has gone to infrared photochemistry. Molecules irradiated with a powerful electromagnetic wave in the infrared remain in the electronic ground state (in the Born–Oppenheimer sense), but their vibrational modes may become highly excited. As a result, infrared‐laser radiation often profoundly affects chemical reaction rates. The absorption of 30 or more infrared photons can raise a molecule into a highly excited vibrational state, leading to some intriguing problems in physical chemistry, quantum electronics and statistical mechanics.