Physics
Proton-electron coordination captured in real-time X-ray study
Scientists have used ultrafast X-ray techniques to observe how electrons and protons move together during a light-driven energy transfer reaction.
A team led by the Department of Energy's Pacific Northwest National Laboratory, with researchers at SLAC National Accelerator Laboratory and several universities, has published a study in Nature Communications that captures snapshots of a light-triggered proton-coupled electron transfer reaction. The findings, reported by ScienceDaily, could eventually help design more efficient flow batteries, fuel cells and catalysts.
What they did
The researchers used ultrafast X-ray spectroscopy and X-ray scattering at SLAC's Linac Coherent Light Source, combined with quantum chemistry calculations and molecular dynamics simulations. They studied a ruthenium-based molecule that absorbs light and, in acidic conditions, picks up a proton from its surroundings.
For the first time with structural sensitivity, the team showed how the molecule's electronic structure changes at specific sites as it gains a proton, while the surrounding water network reorganizes simultaneously.
One study, not a consensus
The experiment examined a single, well-studied molecule to keep the signals clean. "We identified the metal complex used in this study because it does not undergo additional electronic and structural rearrangements that complicate interpretation of X-ray signals," said Christopher Larsen, a co-investigator at the University of Auckland.
A limitation worth noting
Biasin pointed out that the X-ray scattering cannot see the proton directly. "We observe the local reorganization of the electronic structure, together with the global reorganization of the water networks, and we can draw conclusions based on the agreement between data and calculations," she told ScienceDaily.
What it means down the road
The combined X-ray method provides a framework for studying proton-coupled electron transfer reactions in more complicated systems. "This is an important first step in combining X-ray scattering and spectroscopy to study these complicated processes in a model system," said SLAC staff scientist David Hoffman. With upgrades to LCLS, the approach may eventually be applied to real problems in catalysis and energy harvesting.
Related stories
Earth
Loneliness may steal nearly 6 years of good health
A new study of more than 277,000 adults links loneliness and social isolation to a loss of healthy years, especially from mental disorders.
Physics
Thorium nuclear clock ticks steadily for 24 hours
A Vienna-led team kept a thorium clock's laser steady for more than a day with no conventional atomic clock holding it in place.
Physics
Fusion shortcut: Heat plasma before compressing it
PPPL physicists propose a more efficient sequence for reaching fusion ignition, potentially reducing energy requirements by going around the highest hurdle.