Flash photolysis is "a technique of transient spectroscopy and transient kinetic studies in which a light pulse is used to produce transient species. Commonly, an intense pulse of short duration is used to produce a sufficient concentration of a transient species suitable for spectroscopic observation" (IUPAC 1997).
In 1967 Ronald Norrish, George Porter, and Manfred Eigen were awarded the Nobel Prize for studies of extremely fast chemical reaction, effected by disturbing the equilibrium by means of very short impulses of energy. The flash photolysis method is one those famous relaxation techniques which were developed by laureates and many other scientists in the last half of twentieth century. As it happens quite often in history of science, a technique developed in wartime has been applied in unexpected way. In 1948, George Porter realized that high