Femtochemistry

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 reconstruct the progress of the reaction as a function of time. == Examples ==

Bromine dissociation Femtochemistry has been used to show the time-resolved electronic stages of bromine dissociation. When dissociated by a 400 nm laser pulse, electrons completely localize onto individual atoms after 140 fs, with Br atoms separated by 6.0 Å after 160 fs. ==See also==