The Nobel Prize in Chemistry 1999 was awarded to Ahmed Zewail "for his studies of the transition states of chemical reactions using femtosecond spectroscopy".
 

This year's Nobel Laureate, Professor Ahmed Zewail, is rewarded for his pioneering investigations of chemical reactions on the time-scale they really occur. This is the same time-scale on which the atoms in the molecules vibrate, namely femtoseconds (1 fs = 10-15 seconds). Only recently have developments in laser technology enabled us to study such rapid processes, using ultra-short laser flashes. Professor Zewail's contributions have brought about a revolution in chemistry, with consequences for many other fields of science, since this type of investigation allows us to understand and predict important processes.
 

The amount of the Nobel Prize Award is SEK 7, 900, 000.