Scientists have used ultrafast X-ray flashes to observe how a molecule changes immediately after absorbing light, according to ScienceDaily. The study shows that individual atoms can reveal different parts of the transformation as energy moves through the molecule.
The research focused on 3-fluoropyridine, a small ring-shaped molecule with nitrogen and fluorine atoms. After a brief ultraviolet laser pulse excites the molecule, it bends out of its usual flat shape and passes through a conical intersection, a short-lived point where electron motion and atomic movement become strongly linked.
Using time-resolved X-ray photoelectron spectroscopy at the European XFEL, the team followed the molecule over delays of just a few picoseconds. A soft X-ray pulse removed deeply bound electrons from either the nitrogen or fluorine atoms, allowing the scientists to track how the local chemical environment changed over time.
According to the researchers, the fluorine atom gave a clearer picture of how vibrations relaxed, while the nitrogen atom reflected both the redistribution of electrons and the molecule’s changing structure. The findings suggest the method could be used to study more complex molecules, biomolecular building blocks and light-harvesting materials.
