Femtochemistry is the science that studies chemical reactions on extremely short timescales, approximately 10^–15 seconds (this is one femtosecond, hence the name). Part of a scientific laboratory at the University of Cologne. ... For other uses, see Chemical reaction (disambiguation). ... To help compare orders of magnitude of different times this page lists times between 10−15 seconds and 10−12 seconds (1 femtosecond and 1 picosecond). ... A femtosecond is the SI unit of time equal to 10-15 of a second. ...

In 1999, Ahmed H. Zewail received the Nobel Prize in Chemistry for his pioneering work in this field. This article is about the year. ... Ahmed Zewail Ahmed Hassan Zewail (Arabic: أحمد زويل) (born February 26, 1946) is an Egyptian American chemist, and the winner of the 1999 Nobel Prize in Chemistry for his work on femtochemistry. ... This is a list of Nobel Prize laureates in Chemistry from 1901 to 2006. ...

Zewail’s technique uses flashes of laser light that last for a few femtoseconds. Femtochemistry is the area of physical chemistry that addresses the short time period in which chemical reactions take place and investigates why some reactions occur but not others. Zewail’s picture-taking technique made possible these investigations. One of the first major discoveries of femtochemistry was to reveal details about the intermediate products that form during chemical reactions, which cannot be deduced from observing the starting and end products. Many publications have discussed the possibility of controlling chemical reactions by this method, but this remains controversial. For other uses, see Laser (disambiguation). ... Physical chemistry is the application of physics to macroscopic, microscopic, atomic, subatomic, and particulate phenomena in chemical systems[1]within the field of chemistry traditionally using the principles, practices and concepts of thermodynamics, quantum chemistry, statistical mechanics and kinetics. ...

The simplest approach and still one of the most common techniques is known as pump-probe spectroscopy. In this method, two or more optical pulses with variable time delay between them are used to investigate the processes happening during a chemical reaction. The first pulse (pump) initiates the reaction, by breaking a bond or exciting one of the reactants. The second pulse (probe) is then used to interrogate the progress of the reaction a certain period of time after initiation. As the reaction progresses, the response of the reacting system to the probe pulse will change. By continually scanning the time delay between pump and probe pulses and observing the response, workers can follow the progress of the reaction in real time.

External links

• The 1999 Nobel Prize in Chemistry, article on nobelprize.org