To record the movement of electrons excited by X-ray radiation, scientists create a thin, approximately 1 centimeter-wide, sheet of liquid water as a target for the X-ray beam. Credit: Emily Nienhuis | Pacific Northwest National Laboratory
Key points:
- Researchers developed all X-ray attosecond transient absorption spectroscopy to isolate the energetic movement of an electron while “freezing” the motion of the larger atom it orbits.
- The technique allows scientists to visualize the movement of electrons in liquid water and see newly ionized molecules as they are formed in real-time.
- The current study represents an exciting direction for experimental physics and helps identify the effects of radiation exposure on objects and people.
For the first time, scientists have isolated the energetic movement of an electron while “freezing” the motion of the larger atom it orbits. The study, published in Science, provides new perspective on the electronic structure of molecules in the liquid phase on a timescale that has previously been unattainable.
Researchers developed all X-ray attosecond transient absorption spectroscopy in liquids to “watch” electrons as they were energized by X-rays. With this technique, they could visualize electrons in their excited states before the bulkier atomic nucleus could 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,” explained senior author Linda Young, professor at the University of Chicago.
After collecting X-ray data, researchers modelled the liquid water response to the X-rays to confirm that the observed signal was confined to the attosecond timescale. They developed a novel computational chemistry technique for detailed characterization of transient high-energy quantum states in water, meaning they could visualize the real-time motion of electrons while the rest of the world stood still.
“The methodology we developed permits the study of the origin and evolution of reactive species produced by radiation-induced processes, such as encountered in space travel, cancer treatments, nuclear reactors, and legacy waste,” said Young.
The team views the current study as the start of an exciting direction for attosecond science and experimental physics. Their new technique represents a key step in understanding the effects of radiation exposure on objects and people.