Researchers from LIDYL (CEA-IRAMIS), in collaboration with the Centre for Free-Electron Laser Science (DESY, Hamburg), the Swiss Federal Institute of Technology Lausanne (EPFL- LACUS), and the Department of physics at Sapienza University of Rome, have achieved the first real-time observation of molecular vibrations.
Researchers from LIDYL (CEA), in collaboration with the Centre for Free-Electron Laser Science (DESY, Hamburg), the Swiss Federal Institute of Technology Lausanne (EPFL-LACUS), and Sapienza University of Rome, have achieved the first real-time observation of molecular vibrations in liquid water with a temporal resolution of only a few femtoseconds. This work opens a new avenue for exploring the fundamental mechanisms of energy transfer in liquids and solutions.
Real-time observation, on the femtosecond timescale, of the stretching vibration of the OH bond in the water molecule.
Understanding how energy dissipates in a liquid environment remains one of the major challenges of ultrafast physical chemistry. In solution, interactions between the solvent and dissolved molecules govern relaxation pathways, chemical reactivity, and charge-transfer processes. However, the earliest stages of these phenomena occur on timescales of only a few femtoseconds and have so far remained largely inaccessible to direct experimental investigation.
In this study, the researchers combined ultrashort five-femtosecond infrared laser pulses with broadband ultraviolet probe pulses as short as two femtoseconds to directly track the vibrational motion of liquid water. They observed coherent oscillations associated with O–H stretching vibrations and their extremely rapid dephasing, a hallmark of the collective interactions occurring within the hydrogen-bond network.
Beyond providing new insight into the fundamental properties of water, these results demonstrate the ability of this approach to follow energy exchange processes between a molecule and its surrounding environment in real time. The technique therefore paves the way for investigating ultrafast dynamics in solvated molecules, including photochemical reactions and charge-transfer processes, in regimes that have previously been beyond experimental reach.
This achievement builds upon a long-standing international collaboration between the teams at LIDYL/Atto, DESY/CFEL, EPFL-LACUS, and their partners. These laboratories are among the world leaders in ultrafast laser science, femto- and attosecond spectroscopy, and condensed-matter dynamics. Maintaining and strengthening this collaboration will be instrumental in developing new experimental approaches aimed at deciphering the fundamental mechanisms governing the dynamics of molecular systems in solution.
Référence
Real-time tracking of the intramolecular vibrational dynamics of liquid water,
Gaia Giovannetti, Sergey Ryabchuk, Ammar Bin Wahid, Hui-Yuan Chen, Giovanni Batignani, Erik P. Månsson, Oliviero Cannelli, Emanuele Mai, Andrea Trabattoni, Ofer Neufeld, Angel Rubio, Vincent Wanie, Hugo Marroux, Tullio Scopigno, Majed Chergui et Francesca Calegari, Communications Chemistry 9 (2026) 57.
Collaboration
- Laboratoire Interactions, Dynamiques et Lasers -LIDYL Groupe Attophysique (CEA-Saclay)
- Centre for Free-Electron Laser Science (DESY, Hambourg),
- The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, Hamburg, Germany
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany
- Physics Department, Universität Hamburg, Luruper Chaussee 149, Hamburg, Germany
- Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL),
- Dipartimento di Fisica, Université de Rome La Sapienza
- Institute of Quantum Optics, Leibniz Universität Hannover, Hannover, Germany
- Schulich Faculty of Chemistry, Technion—Israel Institute of Technology, Haifa, Israel
- Elettra – Sincrotrone Trieste S.C.p.A., S.S. 14 Km 163, 5 in Area Science Park, Trieste, Italy
Contact CEA : Hugo Marroux (Lidyl – Groupe Attophysique).