A research group led by ETH Zurich has now, for the first time, visualized the motion of electrons during a chemical reaction. The new findings in the experiment are of fundamental importance for photochemistry and could also assist the design of more efficient solar cells.
In 1999, Ahmed Zewail was awarded the nobel prize in chemistry for his studies of chemical reactions using ultrashort laser pulses. Zewail was able to watch the motion of atoms and thus visualize transition states on the molecular level. Watching the dynamics of single electrons was still considered a dream at that time. Thanks to the latest developments in laser technology and intense research in the field of attosecond spectroscopy (1 attosecond = 10-18 s) the research has developed fast. For the first time, Prof. Hans Jakob Wörner with colleagues , was able to record electronic motion during a complete chemical reaction. The experiment is described in the latest issue of Science.
The research team irradiated nitrogen dioxide molecules (NO2) with a very short ultraviolet pulse. Subsequently, the molecule takes up the energy from the pulse which sets the electrons in motion. The electrons start rearranging themselves, which causes the electron cloud to oscillate between two different shapes for a very short time, before the molecule starts to vibrate and eventually decomposes into nitric oxide and an oxygen atom.