Atomic Freeze-Frame: Electron Motion in Water Captured For First Time

Scientists have successfully captured the movement of electrons in liquid water for the first time, opening up new possibilities in experimental physics.


A Breakthrough in Experimental Physics

In a groundbreaking experiment, researchers have managed to isolate the movement of electrons in liquid water while freezing the motion of the atoms they orbit. Using a synchronized attosecond X-ray pulse pair, scientists were able to capture the electronic structure of molecules in the liquid phase on a previously unattainable timescale.

By studying the immediate electronic response when a target is hit with an X-ray, researchers gain important insights into the effects of radiation exposure. This technique allows for a deeper understanding of radiation-induced chemistry in various contexts, such as space travel, cancer treatments, nuclear reactors, and waste disposal.

Unveiling the Secrets of Electron Motion

The research team, consisting of scientists from multiple Department of Energy national laboratories and universities in the U.S. and Germany, combined experiments and theory to observe in real-time the consequences of ionizing radiation from an X-ray source hitting matter.

By working on the timescales where the action happens, the researchers can unravel the complexities of radiation-induced chemistry. Their initial focus was on understanding the effects of prolonged exposure to ionizing radiation on the chemicals found in nuclear waste. The study was supported by the IDREAM Energy Frontier Research Center and conducted at the Linac Coherent Light Source.

Pushing the Boundaries of Attosecond Science

To capture the high-speed movement of subatomic particles, researchers had to employ the cutting-edge field of attosecond physics. Attosecond X-ray pulses are only available in a limited number of specialized facilities worldwide. In this study, the researchers used the Linac Coherent Light Source at SLAC National Accelerator Laboratory in California.

The new technique developed in this study, called X-ray attosecond transient absorption spectroscopy in liquids, allowed researchers to observe electrons being energized by X-rays and moving into an excited state before the atomic nucleus could react. The team used liquid water as their test case and discovered that previous X-ray signals were not evidence for different structural motifs, but rather the result of moving hydrogen atoms.

This breakthrough opens up a whole new direction for attosecond science and provides a powerful tool for studying the origin and evolution of reactive species produced by radiation-induced processes.