Zewail, << zuh WAYL, >> Ahmed Hassan (1946-2016), won the 1999 Nobel Prize for chemistry for his experiments showing how molecules change during chemical reactions. In such reactions, chemical bonds (attractions between atoms that make up molecules) form and break extremely rapidly. And in many cases, what seems to be a single reaction actually takes place in two or more steps. Zewail and his colleagues at the California Institute of Technology (Caltech) in Pasadena developed the first experimental techniques that are fast enough to detect such steps and measure their speed. In these techniques, brief pulses of laser light produce and measure the reactions.
The steps of a chemical reaction occur on a scale of femtoseconds. One femtosecond is one-millionth of one-billionth of a second—a number written out as a decimal point followed by 14 zeros and a 1. Because the area of chemistry pioneered by Zewail involves this scale of speed, it has been given the name femtochemistry (see Femtochemistry ).
Zewail was born on Feb. 26, 1946, in Damanhur, Egypt, east of Alexandria. In 1974, he received his Ph.D. in chemistry from the University of Pennsylvania. He worked as a research fellow at the University of California in Berkeley until 1976, when he joined the Caltech faculty. Zewail became a full professor at Caltech in 1982. In the same year, he became a United States citizen. Zewail died on Aug. 2, 2016.
