Ultrabright electrons shed light on organic chemistry

It is now possible — using ultrafast diffraction methods — to directly observe atomic motions in condensed-phase processes. But organic materials, in which so many important chemical and biological interactions take place, are a different matter. Weak scattering centres, thermal lability and poor heat conduction often degrade the sample before useful data can be obtained. However, a recent technical breakthrough has delivered an ultrabright femtosecond electron source that can operate at a low repetition rate, and this has now been used by Meng Gao et al. to record time-delayed diffraction patterns with sufficient quality to map the molecular motions associated with the photo-induced charge delocalization in an organic salt. These findings illustrate the potential for ultrabright femtosecond electron sources in studies that aim to probe complex dynamic structural process in labile systems relevant to chemistry and biology.