15/03/2022
Cavity quantum optics deals with the interactions of photons and molecules inside an optical cavity, i.e., in the region between two closely spaced mirrors. Perfect optical cavities can only support certain frequencies of light. In addition, the intensity of the associated electromagnetic field is enhanced by the confinement. This leads to profound changes in chemical reactivity when molecules are placed inside an optical cavity. The formation of hybrid states (polaritons) having both matter and light character allows for the optical manipulation of reactive events on demand. This aspect has already been observed in the pioneering experiments performed by Prof. Thomas Ebbesen’s group at the University of Strasbourg. However, the physics underlying these phenomena is still not fully understood.
The simplest approach that theoretical chemists commonly use to gain information about chemical reactivity is based on molecular orbital analysis. This tool allows, through a visual representation of the electrons in space, an intuitive interpretation to chemical reactivity. The picture provided by molecular orbital theory can be easily translated into the reaction mechanisms usually employed in organic chemistry. Despite the increased popularity of the strong coupling problem, a molecular orbital theory for molecules in optical cavities had not yet been developed.
The work by Rosario R. Riso, PhD student at the Norwegian University of Science and Technology, and colleagues, represents the first molecular orbital theory able to incorporate the effect of a quantized electromagnetic field in a consistent manner. The approach is able to provide an intuitive and visual interpretation of chemical reactivity and at the same time describe a significant part of the electron-photon interaction. Moreover, the method will be the starting point for the formulation of ab initio perturbation theories for coupled electron-photon systems. “The new framework will be also crucial to model, in a simple way, ionization processes in the strong coupling regime”- says the corresponding author Prof. Henrik Koch from SNS and NTNU.
The team is composed of researchers from several European institutions: Scuola Normale Superiore (SNS) and Istituto per i processi chimico-fisici (Ipcf) of the National Research Council of Italy, both in Pisa (Italy) and the Norwegian University of Science and Technology (NTNU) in Trondheim (Norway).
Per informazioni:
Enrico Ronca
CNR - Istituto per i processi chimico-fisici
Via G. Moruzzi 1, 56124, Pisa
enrico.ronca@pi.ipcf.cnr.it
0503152250
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