Work

Time-resolved Coulomb explosion imaging of a photochemical ring opening reaction

Year: 2026

Type: article

Abstract: Photoinduced transformations of organic ring molecules play a crucial role in numerous physical, chemical and biological processes, ranging from biosynthesis of vitamin D to optical switching in molecular electronics. Although the development of a plethora of ultrafast techniques such as time-resolved photoelectron spectroscopy, ultrafast electron and x-ray diffraction and transient x-ray absorption has recently enabled detailed investigations of the electronic and nuclear dynamics in several ring conversion reactions, direct and unambiguous imaging of the nuclear motion, especially during the first 100 fs of a reaction, is still a major challenge. As a consequence, the reaction mechanisms often remain controversial even for extensively studied prototypical systems. Here we show how time-resolved Coulomb explosion imaging can be used to directly map the molecular ring rearrangement upon ultraviolet excitation of gas-phase furan, a reaction for which widely contradicting predictions and observations have been reported. By directly imaging the motion of the individual atoms of the carbon backbone of the molecule upon excitation at 198 nm, we reveal the presence of a strong ring-opening pathway that is completed in less than 70 fs. With the development of higher repetition rate lasers, we anticipate that our approach will enable atom-by-atom mapping of a broad range of ultrafast photochemical reactions.

Source: Nature Communications

DOI: 10.1038/s41467-026-75191-6