The Royal Swedish Academy of Sciences has awarded the 1999 Nobel Prize in Chemistry to Professor Ahmed H. Zewail , California Institute of Technology, Pasadena, USA for showing that it is possible with rapid laser technique to see how atoms in a molecule move during a chemical reaction. This year's laureate in Chemistry is being rewarded for his pioneering investigation of fundamental chemical reactions, using ultra-short laser flashes, on the time scale on which the reactions actually occur. Professor Zewail's contributions have brought about a revolution in chemistry and adjacent sciences, since this type of investigation allows us to understand and predict important reactions.
Chemical reactions are a similar case.
The chemists' eagerness to be able to follow chemical reactions in the greatest detail has prompted increasingly advanced technology. Zewail's technique uses what may be described as the world's fastest camera. One femtosecond is 10 - 15 seconds, that is, 0.000000000000001 seconds, which is to a second as a second is to 32 million years. This area of physical chemistry has been named femtochemistry. Femtochemistry enables us to understand why certain chemical reactions take place but not others.