Role of Symmetry in Vibrational Strong Coupling

Our latest paper is online and open access in Angewandte Chemie. We explore and reveal the critical role of molecular symmetry in vibrational strong coupling (VSC) in the case of a charge-transfer (CT) complexation reaction. We show indeed that VSC induces large changes in the equilibrium constant of the mesitylene-I2 CT complex, which can be either enhanced or suppressed depending only on the symmetry of the
vibration coupled to the vacuum electromagnetic field.


Thermodynamics of VSC

A new publication appeared last week in Nanophotonics, where we study the evolution of some thermodynamic parameters of a chemical reaction (desilylation of PTA) happening in an optical cavity, under vibrational strong coupling (VSC). In this regime, the enthalpy and entropy of activation, determined from temperature-dependent kinetics studies, vary nonlinearly with the coupling strength whereas, when the same parameters are characterized out of cavity, they are pretty constant. It confirms that changes in the kinetics observed under VSC are only related to the enhanced coupling strength. Those results give more insight into the role of collective strong coupling on the transition state that leads to modified dynamics and branching ratios. See our publications page !

Back to school…

We are pleased to announce that a new publication, in cooperation with Vladimir Torbeev group, has just been accepted in Angewandte Chemie International Edition. This time we applied the concept of strong-coupling induced cooperative effect to a biological molecule, the pepsin, which is a digestive enzyme. When strongly coupling the OH stretching bond of the water surrounding pepsin (and involved in its chemical mechanism), the enzyme activity, characterized by fluorescence spectroscopy, is modified. Being able to alter the energy landscape of biological molecules opens a new and promising way to studies on biochemical reactivity. The paper is open access and has been tagged as VIP paper. You can also download it in our Publications page.

One more for the week-end !

Dr Jino George is now leading his group at IISER Mohali but still collaborating with the lab and we are pleased to announce that our paper, previously on ChemArXiv is now accepted for publication in Angewandte Chemie. It reports the solvolysis of PNPA catalysed by vibrational strong coupling (VSC) under cooperative strong coupling effect between the reactant and the solvent molecules. More precisely, when the solvent and reactant have the same vibrational bands, but only the solvent is at a concentration high enough to be strongly coupled to the cavity mode, the reaction rate is increased by one order of magnitude at room temperature. These results offer an exciting perspective for the control of chemical reactivity under VSC regime.

New publications

We added two more papers in our publications page.

One is a recent review written by two groups of ISIS (ours and Thomas Hermans one), including also three researchers from United-Kingdom and Sweden. It deals with the mechanical separation of chiral objects, in particular at the colloidal scale and the way of achieving it by new methods.

The second presents the results of a collaboration, this time with theoreticians colleagues of the DYNO group at IPMCS and a mathematician from NYU Shangaï. It proposes to control the dynamics of a stochastic system from one thermal equilibrium to another, via some optimized protocols that are tested experimentally on a particle in an optical trap.

Photons, phonons, plasmons…

A new publication from Guido Pupillo‘s team, in collaboration with us, just appeared in the asap section of ACS Photonics. It shows that, intrinsic surface plasmon-phonon polaritons in a metallic crystal, resulting from hybridized plasmons-phonons modes coupled to photonic degrees of freedom, offer a unique opportunity to control the material properties of the crystal, without the use of an external resonator. More details in the publications page.

Femtonewtons and tens of picometers

Another publication appeared in Physical Review Applied last week ! This study presents a method to measure radiation pressure on metallic nanoparticles down to the thermal limit, with a large dynamic range and fine resolution in position. This is made possible by a careful assessment of the conditions of stability through an Allan-based deviation analysis. The capacity to measure femtonewton forces is important in the context of optical spin-orbit interactions and chiral forces.

Action in the Dark

This is nor the last trendy horror movie, neither the latest Star Wars episode but just another reaction about our Science paper, now online in the asap section of ACS Central Science. It has been written by Stéphane Kéna-Cohen and Joel Yuen-Zhou and it is entitled Polariton Chemistry : Action in the Dark. The paper is open access (published under ACS Author Choice license) and you can download it here.

Source : ACS Central Science