Ultrafast X-rays capture chemistry unfolding atom by atom

Researchers at the European XFEL have achieved a breakthrough in observing chemical reactions at the atomic scale. By using ultrafast X-ray pulses, they tracked how a molecule known as 3-fluoropyridine moves when it absorbs ultraviolet light. This process happens in just trillionths of a second.

The team found that individual atoms within the molecule register different parts of this transformation. While some atoms indicate where charge moves, others highlight how the molecular structure vibrates. This level of detail offers a direct look at the fundamental mechanics of light-driven chemistry.

To capture these movements, scientists used time-resolved X-ray photoelectron spectroscopy. By delaying the X-ray pulses after the initial light exposure, they reconstructed the sequence of events. The data provides a clear picture of how energy shifts through a molecule, including its passage through critical points where electronic and structural motions couple.

This method holds significance for future studies in material science and biology. Understanding how energy travels at this speed is essential for learning how molecules like DNA survive light exposure or how materials efficiently harvest solar energy. The study marks a step forward in capturing the specific atomic mechanisms that govern photochemical reactions.