Physicists have successfully captured the real-time break-up of C60 fullerenes, commonly known as Buckminsterfullerenes, using advanced X-ray imaging techniques. This significant breakthrough in molecular dynamics was achieved through a collaboration involving researchers from multiple institutions, including the Max Planck Institute for Nuclear Physics in Heidelberg and the Max Planck Institute for the Physics of Complex Systems in Dresden. The results, published on November 21, 2025, in the journal Science Advances, mark a pivotal moment in the study of laser-driven chemical reactions.
Understanding the complex many-body dynamics within polyatomic molecules is essential for advancing technologies that manipulate chemical reactions using intense light fields. The researchers utilized ultrashort and intense X-ray pulses generated by accelerator-based free electron lasers (FELs) to observe how strong laser fields reshape molecules. The X-ray images were captured at the Linac Coherent Light Source (LCLS) located at the SLAC National Accelerator Laboratory in California.
The study focused on C60, a molecule shaped like a soccer ball, and aimed to investigate its behavior under varying laser intensities. By analyzing the time-dependent X-ray diffraction patterns resulting from a strong infrared (IR) laser pulse, the team was able to extract critical parameters: the average radius (R) of the molecule and the Guinier amplitude (A). The latter serves as an indicator of the strength of the X-ray scattering signal, which is proportional to the squared number of atoms acting as scattering centers.
The findings revealed distinct behaviors at different laser intensity levels. Under low intensity (1×10^14 W/cm²), the C60 molecule expanded before exhibiting any fragmentation. At intermediate intensity (2×10^14 W/cm²), the molecule’s expansion was followed by a noticeable decrease in the radius as small fragments began to scatter. Finally, at the highest intensity (8×10^14 W/cm²), the rapid expansion coincided with a significant reduction in the Guinier amplitude, indicating that the majority of the outer valence electrons had been stripped away.
Despite the promising results, discrepancies between experimental observations and theoretical predictions were noted, particularly at lower intensities. The models anticipated an oscillatory behavior caused by periodic “breathing” of the molecule, which was absent in the collected data. To improve alignment between the theoretical and experimental findings, researchers incorporated an ultrafast heating mechanism to account for variations in atomic positions within the molecule.
This research is crucial as it sheds light on the intricate dynamics of multi-electron systems influenced by intense laser fields. As a full quantum mechanical treatment remains challenging, the real-time imaging of molecular dynamics in C60 offers a valuable platform for exploring fundamental quantum processes. The insights gained may pave the way for future advancements in controlling chemical reactions through laser interactions.
For further details, refer to the original publication: Kirsten Schnorr et al., “Visualizing the strong-field induced molecular break-up of C60 via X-ray diffraction,” Science Advances, DOI: 10.1126/sciadv.adz1900.
