A research team led by Argonne National Laboratory physicists has isolated the energetic movement of an electron while ‘freezing’ the motion of the much larger atom it orbits in a sample of liquid water.
“The chemical reactions induced by radiation that we want to study are the result of the electronic response of the target that happens on the attosecond timescale,” said study’s senior author Professor Linda Young, a researcher at Argonne National Laboratory.
Professor Young and her colleagues combined experiments and theory to reveal in real-time the consequences when ionizing radiation from an X-ray source hits matter.
Working on the time scales where the action happens will allow them to understand complex radiation-induced chemistry more deeply.
Indeed, the researchers initially came together to develop the tools needed to understand the effect of prolonged exposure to ionizing radiation on the chemicals found in nuclear waste.
“Attosecond time-resolved experiments are one of the flagship R&D developments at the Linac Coherent Light Source,” said study’s co-author Dr. Ago Marinelli, a researcher at the SLAC National Accelerator Laborator.
“It’s exciting to see these developments being applied to new kinds of experiments and taking attosecond science into new directions.”
The technique developed by the scientists — all X-ray attosecond transient absorption spectroscopy in liquids — allowed them to ‘watch’ electrons energized by X-rays as they move into an excited state, all before the bulkier atomic nucleus has time to move.
“We now have a tool where, in principle, you can follow the movement of electrons and see newly ionized molecules as they’re formed in real-time,” Professor Young said.
The findings resolve a long-standing scientific debate about whether X-ray signals seen in previous experiments are the result of different structural shapes, or motifs, of water or hydrogen atom dynamics.
These experiments…
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