06 November 2025 - The research team including Giulio Cerullo, professor in the Department of Physics, Politecnico di Milano, Caterina Vozzi from the CNR Institute of Photonics and Nanotechnology, Marco Garavelli from the University of Bologna, and Shaul Mukamel from the University of California has been awarded a €10 million ERC Synergy Grant to “film” molecules as they change shape under the effect of light, and to learn how to guide these transformations.
When light strikes a molecule, it can trigger ultra-fast chemical transformations, which occur in timescales of a few millionths of a billionth of a second. These processes underlie essential biochemical phenomena such as vision, photosynthesis or DNA protection from UV radiation. However, what exactly happens during these reactions is still largely mysterious as it happens too fast to be observed with traditional techniques.
The CONCERT project (Capturing and cONtrolling coniCal intErsections in Real Time) aims to address this challenge by combining experimental and theoretical expertise in physics, chemistry and laser technology.
The project’s principal aim is to observe conical intersections - critical points in the “energy map” of light-excited molecules - where two electronic states intersect. In such instants, the classical rules of chemistry cease to apply, and molecules follow purely quantum behaviour. If we imagine a molecule as a car moving along a trajectory, we can picture the conical intersections as quantum “traffic junctions”, or “molecular roundabouts” that determine along which of several possible trajectories the molecule will evolve. Understanding how it works offers the possibility of controlling photochemical reactions by deflecting the path of molecules with a light flash to channel them in the desired direction from the many available at the “molecular roundabout”.
To observe such rapid phenomena, CONCERT will develop next generation laser instruments capable of emitting ultra-short pulses of light, which last only a few millionths of a billionth of a second, to create a kind of “molecular movie”. An initial laser pulse starts the chemical process. A second pulse takes a snapshot of the molecule's state. By repeating the operation with different time delays, a movie of molecular evolution is constructed to record the passage of the molecule through the conical intersection. Part of these experiments will be carried out at FERMI, the free-electron laser at Sincrotrone ELETTRA in Trieste: “with its light pulses in soft X-rays, FERMI allows to observe, in real time, how molecules behave and transform during conical intersections,” says Claudio Masciovecchio, Director for time-resolved experimental techniques at Elettra Sincrotrone Trieste.
Once it is understood how light determines the evolution of molecules, the next step is to use light itself to control it. CONCERT aims to design customised laser pulses that interact with the molecule as it approaches the conical intersection to direct the path of the chemical reaction, choosing which product to obtain. «Traditional methods have tried to control the reaction from the very beginning, but have so far proved inefficient,» says Marco Garavelli. «We propose a paradigm shift. Instead of controlling the start, we apply a specially designed laser pulse at the critical point - the conical intersection - where the molecule 'chooses' its path».
This approach is a long-standing dream of chemists, to use light as a catalyst able to control the outcome of a chemical reaction without adding external substances. «To date, scientists have largely only been spectators of these “molecular movies," says Giulio Cerullo. «While we shall develop special “cameras” to catch these events the instant they occur, our ultimate goal is to become active filmmakers, instead of passive observers.»
The success of CONCERT will not only open a new window into the more intimate nature of photochemical reactions, but may have an important impact on green chemistry for clean and selective synthesis of new compounds, and on materials technology to design photosensitive molecules and photonic devices inspired by biological processes. «In other words, the project aims to combine quantum physics, ultrafast lasers and molecular chemistry to create a new frontier, namely quantum chemical synthesis controlled by light,» concludes Caterina Vozzi.
Giulio Cerullo is Full Professor of Physics of Matter at the Department of Physics, Politecnico di Milano. He leads an experimental ultrafast optical spectroscopy research team, which aims to generate ultra-short light pulses and use them to study dynamic processes in molecules and materials.
He is a corresponding member of the Accademia dei Lincei, and a fellow of both the Optical Society and the European Physical Society. In 2023, he received the Quantum Electronics Prize from the European Physical Society.
Caterina Vozzi is Director of the Institute of Photonics and Nanotechnology of the National Research Council (CNR). He leads an experimental research team that has significantly contributed to the fields of attosecond science, atomic and molecular spectroscopy based on high-order harmonic generation and time-resolved X-ray spectroscopy.
Marco Garavelli is professor at the University of Bologna's “Toso Montanari” Department of Industrial Chemistry. He is involved in developing methods and applications in computational (photo)chemistry, photobiology and spectroscopy, with a focus on simulating the photoreactivity of complex molecular systems in their operational environment, including complex non-linear spectroscopies. A former ERC Advanced Grant winner, he has also received the Primo Levi Prize from the Italian Chemical Society. He has headed and still leads numerous international (EU and US funded) and national (PRIN) projects.