The development of ultrafast gas electron diffraction with nonrelativistic electrons has
enabled the determination of molecular structures with atomic spatial resolution. It has,
however, been challenging to break the picosecond temporal resolution barrier and achieve
the goal that has long been envisioned—making space-and-time resolved molecular movies
of chemical reaction in the gas-phase. Recently, an ultrafast electron diffraction (UED)
apparatus using mega-electron-volt (MeV) electrons was developed at the SLAC National …