Femtochemistry is the science that studies chemical reactions on extremely short timescales, approximately 10^-15 seconds (this is one femtosecond, hence the name).

Femtochemistry often utilizes ultrashort pulse laser beams to study the mechanics of chemical reactions.

In 1999, Ahmed H. Zewail received the Nobel Prize in Chemistry for his pioneering work in this field.

Importance of Femtochemistry

The contribution for which Zewail is to receive the Nobel Prize means that we have reached the end of the road: no chemical reactions take place faster than this. With femtosecond spectroscopy we can for the first time observe in 'slow motion' what happens as the reaction barrier is crossed and hence also understand the mechanistic background to Arrhenius equation for temperature dependence and to the formula for which van't Hoff was awarded his Nobel Prize.

Femtosecond studies following Zewail's work are being performed intensively the world over, using not only molecular beams but also processes on surfaces (e.g. to understand and improve catalysts), in liquids and solvents (to understand mechanisms of the dissolving of and reactions between substances in solution) and in polymers (e.g. to develop new material for use in electronics). Another important research field is studies of biological systems. Knowledge of the mechanisms of chemical reactions is also important for our ability to control the reactions. A desired chemical reaction is often accompanied by a series of unwanted, competing reactions that lead to a mixture of products and hence the need for separation and cleansing. If the reaction can be controlled by initiating reactivity in selected bonds, this could be avoided.

Femtochemistry has fundamentally changed our view of chemical reactions. From a phenomenon described in relatively vague metaphors such as activation and transition state, we can now see the movements of individual atoms as we imagine them. They are no longer invisible. Here lies the reason why the femtochemistry research initiated by this year's Nobel Laureate has led to explosive development. With the world's fastest camera available, only the imagination sets bounds for new problems to tackle.

Scientists the world over are studying processes with femtosecond spectroscopy in gases, in fluids and in solids, on surfaces and in polymers. Applications range from how catalysts function and how molecular electronic components must be designed, to the most delicate mechanisms in life processes and how the medicines of the future should be produced.

probing will no doubt bring a new interpretation to such cherished concepts of chemistry as resonance, breaking and forming of chemical bonds, their energies, and their covalent or ionic nature.

Zewail's technique, using what could be described as the world’s fastest camera, makes it possible to watch individual atoms during a chemical reaction in the same way that viewers can watch details of a football match in a slow-motion replay.

The technique helps explain why certain chemical reactions take place but not others and why the speed and yield of those reactions depend on temperature.