Elusive water ionisation intermediate found using ultrafast x-ray pulses

An image showing a water droplet

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H2O+ cationic hole never directly observed before

Photo-ionisation of liquid water is crucial to numerous corrosion processes – including DNA damage that can lead to cancer in humans. However, one of the intermediates in this reaction had never been clearly detected. Now, however, researchers have used ultrashort x-ray laser pulses to detect clear evidence of its existence and measure its lifetime.