UnMySt - ERC Synergy Project

UnMySt – Unravelling the Mysteries of Vibrational Strong Coupling    
UnMySt is an international research project that explores how vibrational strong coupling in optical cavities can be used to steer chemical reactivity and material properties. Our goal is to transform polaritonic chemistry into a practical tool in synthetic chemistry and material design. The project is funded by the European Research Council under the Synergy Grant Scheme, and it unites leading experimental and theoretical groups in polaritonic chemistry.

Vibrational strong coupling has emerged as a powerful way to modify materials and ground chemical reactivity, even in the absence of light. While the scientific and technological potential is clear, the underlying mechanisms driving these changes remain a mystery. UnMySt aims to solve this puzzle, moving from simple observations to a predictive framework. Over the six-year period of the project, we will jointly pursue these key questions:

Local vs. collective reactivity: How do local reaction coordinates couple to delocalized polaritonic modes?       
Equilibrium properties: To what extent do thermodynamic and structural properties change in a cavity?       
Non-equilibrium dynamics: How are solvent reorganization, charge and energy transfer modified under VSC?     
Symmetry and design: Can cavity-imposed or broken symmetries be used to enhance or suppress specific reaction pathways?   

The UnMySt Team
The UnMySt project employs a multifaceted approach, merging experimental and theoretical efforts to bridge the conceptual gaps presented by vibrational strong coupling and polaritonic chemistry. Our international consortium comprises four distinct nodes, each contributing complementary methodologies and perspectives:

Strasbourg Group: Led by Thomas Ebbesen who envisioned and pioneered the field of polaritonic chemistry, this node explores chemical reactivity under Vibrational Strong Coupling (VSC). A key focus of these studies is the role of molecular and electromagnetic symmetries, spearheaded by Cyriaque Genet
Tel Aviv Group: Led by Tal Schwartz, this node focuses on ultrafast time-resolved spectroscopy measurements. In collaboration with Sharly Fleischer, the group probes dynamics across the entire spectral range, spanning the visible, mid-infrared, and Terahertz regimes. 
Hamburg Group: Led by Angel Rubio and based at the Max Planck Institute for the Structure and Dynamics of Matter, this node develops ab initio simulations of strongly coupled materials. This work leverages the expertise of Michael Ruggenthaler in mathematical modeling and Dominik Sidler in simulations of non-canonical VSC systems.   
Pennsylvania Group:
Led by Abraham Nitzan at U. Penn, this node focuses on macroscopic classical and semiclassical modeling, including the formulation of novel reaction-rate theories adapted for VSC. This effort utilizes state-of-the-art Maxwell–Schrödinger simulations, developed together with Maxim Sukharev at Arizona State University.    


News & Highlights
New Publication:  Molecular Polariton Dynamics in Realistic Cavities. 
A cost-effective computational method is introduced, combining Maxwell’s equations with quantum molecular dynamics to simulate how large groups of molecules interact with light inside realistic mirrored cavities. This approach allows to observe how the position and orientation of individual molecules influence both collective light signals and unique local chemical responses. 
New Publication: Effective equilibrium theory of quantum light-matter interaction in cavities for extended systems and the long wavelength approximation. 
This publication establishes an effective, non-perturbative ab-initio theory for Fabry-Pérot cavities that simplifies quantum light-matter interactions in extended 2D systems by reducing a complex continuum of electromagnetic states into a few discrete photonic modes. Most importantly, it is demonstrated that the interaction volume remains finite even in the bulk limit.
 
A stimulating beginning: The UnMySt Synergy Project was officially launched in a kick-off meeting held in Strasbourg on 20-22 May, 2025. It was an opportunity for all the participants to meet and start to know each other, their skills and projects, and to define together the way we would like to handle the next meetings and the topics to target for the future.