Organic Photochemistry

There is an activation energy associated with all chemical reactions, and therefore no chemical transformations are possible without some input of external energy. This activation energy may be very small in some reactions, which therefore occur even at low temperatures. It may be so high in other cases that desired reactions cannot be performed in the dark no matter how high the temperature is raised. Instead, decomposition and production of other unwanted products are observed. Although frustrating in practice, this decomposition is easily explained by looking at the energetics of chemical bonds.