Scientists observe ultrafast birth of free radicals in water

What they learned could lead to a better understanding of how ionizing radiation can damage material systems, including cells.

Understanding how ionizing radiation interacts with water—like in water-cooled nuclear reactors and other water-containing systems—requires glimpsing some of the fastest chemical reactions ever observed.

In a new study conducted at the Department of Energy’s SLAC National Accelerator Laboratory, researchers have witnessed for the first time the ultrafast proton transfer reaction following ionization of liquid water. The findings, published today in Science, are the result of a world-wide collaboration led by scientists at the DOE’s Argonne National Laboratory, Nanyang Technological University, Singapore (NTU Singapore) and the German research center DESY.

The proton transfer reaction is a process of great significance to a wide range of fields, including nuclear engineering, space travel and environmental remediation. This observation was made possible by the availability of ultrafast X-ray free electron laser pulses, and is basically unobservable by other ultrafast methods. While studying the fastest chemical reactions is interesting in its own right, this observation of water also has important practical implications.

>Read more on the LCLS at SLAC website

Image: X-rays capture the ultrafast proton transfer reaction in ionized liquid water, forming the hydroxyl radical (OH) and the hydronium (H3O+) ion. Credit: Argonne National Laboratory