Edited sentence: , over minutes or days).Ahmed Zewail is a creative and Nobel Prize winning pioneer of this technique.At one extreme are scientists who are concerned with the ultimate outcome of a photochemical reaction (i.At the other extreme are scientists who are  interested in the ultra-short timescale (femtosecond) events during which electrons find new places to be (including making new bods) after absorbing light.Environmental photochemists, for example, tends to utilize long term radiation exposure as an experimental technique (Richard Zepp is one such who is probably deserving of a Wikipedia entry).In between are folks interested in studying how molecules redistribute the energy gained from light absorption (as vibrations.There are several subdisciplines within photochemistry itself, depending upon the time frame of interest.Tools for studying this intermediate time scale (like fluorometry) can also be exploited in many ways to find out where molecules are located in heterogeneous media or what their conformations are (think proteins).bond dissociation after vibration