Molecular "Hollywood": super high speed imaging technology helps chemists shoot molecular videos

Every chemist is a dreamer Every day, they imagine molecules floating in space They rotate this structure in their mind, look at them from multiple perspectives, and let each molecule rotate until one chemical bond is broken and another chemical bond is formed Such projection patterns exist in the minds of almost all chemists because they provide a "visual" reflection of how chemical reactions occur After the discovery of molecular structure for the first time, chemists have had this dream for more than 150 years Now, dreams are coming true Researchers are using a range of techniques to direct molecular films in the laboratory, most of which interpret scenes with incredible short pulses of light or electrons Some of them rely on the atomic precision of scanning tunneling microscope (STM), while others use the intense X-ray bursts to reveal the target structure Their goal is to photograph events that occur between picoseconds or femtoseconds, in which atoms move only at the picosecond level (a hydrogen atom is about 100 picoseconds in diameter) At this resolution, for the first time, researchers can directly observe a molecule's peristalsis, atomic bond vibration and fracture or electron back and forth swing in slow motion As these technologies become more and more mainstream, the benefits will be huge They can provide key information for better catalysis and artificial photosynthesis, or provide new channels for computing and communication of quantum characteristics of manipulation molecules The European X-ray free electron laser near Hamburg, Germany (source: nature) recently, chemists have a new high-speed camera, which can be used to take pictures of molecules in motion It is the 1.2 billion euro (about 1.4 billion US dollars) European X-ray free electron laser (xfel), which has recently started the first experiments near Hamburg, Germany This machine is one of several X-ray laser facilities around the world, but it has a unique fast shooting feature: it can emit up to 27000 pulses per second, and the emission speed exceeds the second-largest X-ray laser facility - the $420 million Stanford Linear Accelerator Center (SLAC) in Menlo Park, California, U.S.A At the same time, its brightness is 1 billion times higher than the traditional synchrotron light source "It's a different guy than anything else on earth, and it feels like it's entering an unknown territory." Arwen Pearson, a biochemist at the free electron laser science center in Hamburg, said The electron beam in the facility first Accelerates along a 1.7-kilometer-long tunnel, and then the magnet bends the electron path into a swinging orbit, making it emit a high-energy x-ray beam when bent Bright X-ray pulses are so intense that they can destroy the sample they hit, but they haven't been destroyed until enough photons are scattered to reveal the atomic structure of the sample In the structure determination experiments using traditional X-ray sources, molecules must be loaded into the crystal to scatter enough photons to infer its structure However, X-rays from xfel are so bright that researchers can collect diffraction patterns from crystals several nanometers in size, or even from noncrystalline clusters of molecules This means that xfel can study proteins that are difficult to crystallize Researchers take thousands of different snapshots of the same system at different points in time, and then combine them to create dynamic images of enzymes, viruses or catalysts - usually by spraying a molecular solution through an X-ray beam X-ray laser can not only be used to solve the mystery of virus and cell atomic structure, but also be used to make three-dimensional images in nanoparticles, record chemical reactions and observe the reaction process inside particles, which is helpful for the research and development of new drugs and materials Hamburg's device has more capacity than its competitors: unlike xfel, which has three independent undulators, it can generate x-ray beams at the same time But the European xfel will only dominate for a limited time: the US National Accelerator Laboratory has started a $1 billion project this year to create a brighter laser beam - which will be able to fire 1 million pulses per second by around 2020.