How to catch an elusive water ion
In a world-first, NTU physicists led by Assoc Prof Loh Zhi Heng directly observed water ions that form and break down within a time span of less than 50 femtoseconds.
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Water ions—positively charged water molecules lacking one electron—have never been observed directly due to their extremely short life span of less than 50 femtoseconds.
Using an ultrafast X-ray laser, a team of physicists—jointly led by NTU, the US Department of Energy’s Argonne National Laboratory and Germany’s Deutsches Elektronen-Synchrotron DESY—succeeded in observing the formation and breakdown of a highly unstable water ion, which is created when water is exposed to ionising radiation.
“What we are observing is the very first chemical reaction in a cascade of reactions that ultimately leads to radiation damage,” says Assoc Prof Loh Zhi Heng of NTU’s School of Physical and Mathematical Sciences.
A better understanding of this chemical reaction could pave the way towards stopping or reducing radiation damage in biological cells and water-cooled nuclear reactors, he adds.
The paper “Observation of the fastest chemical processes in the radiolysis of water” was published in Science (2020), DOI: 10.1126/science.aaz4740.