Scientists recorded atoms "roaming" just before a radiation burst broke them apart.
- What it is: The work focuses on electron‑transfer‑mediated decay (ETMD). This is a radiation‑driven step that can pull weakly bound atoms apart and make very reactive particles in water.
- How they watched it: Using a special reaction microscope and powerful computer models, the team followed the decay in real time inside a tiny laboratory system.
- What they saw: They created a short "movie" showing atoms moving around each other for up to one picosecond before the system finally split.
- Why it matters: Seeing this motion helps scientists understand how radiation hurts living things at the smallest level. Better knowledge can improve safety models and future protection methods.
How Radiation Hurts Cells
High‑energy rays like X‑rays can shake atoms and molecules inside cells. When they get excited, they often break apart, damaging important biological parts.
Because many different tiny decay steps can happen, researchers study each one to learn how radiation creates damage and how we might reduce it.
Seeing ETMD Up Close
In this study, scientists looked at a simple trio of atoms: one neon atom loosely attached to two krypton atoms (NeKr₂). They knocked an electron out of the neon with soft X‑rays and then watched the whole group for up to a picosecond.
During that time an electron moved from one atom to another, and a low‑energy electron was released.
Using a COLTRIMS reaction microscope at the BESSY II and PETRA III synchrotrons, they recorded the exact positions of the atoms when the decay happened. They paired the measurements with computer simulations that traced thousands of possible paths.
A "Movie" of Atoms on the Move
The atoms didn’t stay still. They roamed, constantly changing places and reshaping the tiny molecule. This wandering changed both when the decay happened and what the result looked like.
Early on, the atoms were close to their original shape. Later, one krypton moved closer to neon while the other drifted away, creating a good spot for electron transfer. At later times the whole structure stretched and twisted, showing a swinging motion that sped up or slowed down the decay.
Why Knowing About ETMD Is Important
ETMD creates low‑energy electrons that can start chemical damage in water and living tissue. Understanding how the atoms’ positions and movement affect ETMD helps scientists build better models of radiation damage in biological environments.
The study offers a clear benchmark for the simplest system that can show ETMD with three atoms. This foundation can be extended to liquids, solvated ions, and more complex biological systems.