First-ever atomic freeze-frame of liquid water

In an experiment akin to stop-motion photography, an international team of scientists has isolated the energetic movement of an electron in a sample of liquid water - while "freezing" the motion of the much larger atom it orbits. The finding reveals the immediate response of an electron when hit with an X-ray, an essential step in understanding the effects of radiation exposure on objects and people. The results, published Feb. 15 in the journal Science, provide a new window into the electronic structure of molecules in the liquid phase on a timescale previously unattainable with X-rays. "What happens to an atom when it is struck by ionizing radiation, like an X-ray? Seeing the earliest stages of this process has long been a missing piece in understanding how radiation affects matter," said co-senior author Xiaosong Li , the Larry R. Dalton Endowed Chair in Chemistry at the University of Washington and a laboratory fellow at the Pacific Northwest National Laboratory. "This new technique for the first time shows us that missing piece and opens the door to seeing the steps where so much complex - and interesting - chemistry occurs!" Li co-led the team behind this breakthrough with co-senior authors Linda Young , a distinguished fellow at Argonne National Laboratory and professor at the University of Chicago, and Robin Santra , professor at the German Electron Synchrotron and the University of Hamburg. The team received critical funding and support from the Interfacial Dynamics in Radioactive Environments and Materials (IDREAM) partnership , a Department of Energy center headquartered at PNNL.