How photons change chemistry

March 16, 2017, Max Planck Institute for the Structure and Dynamics of Matter
A molecule in an optical cavity. Comparing weak (on the left) and strong (on the right) coupling to the photon field shows, besides other effects, that in the case of strong matter-photon coupling the distance between the atoms of the molecule shrinks. Credit: Joerg M. Harms/MPSD

The quantum nature of light usually does not play an important role when considering the chemical properties of atoms or molecules. In an article published in the Proceedings of the National Academy of Sciences scientists from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg show, however, that under certain conditions, photons can strongly influence chemistry. These results indicate the possibility that chemical processes can be tailored by photons.

Experimentally, such situations have already been observed, but theoretical predictions of the of such states were possible only to a limited extent; the common quantum-chemical methods do not take into account the of light. The research group has now extended some of these methods to include the coupling to the . Among other things, the group of Prof. Angel Rubio showed how strong coupling to photons in an changes chemical properties of molecules, like its bond length or its absorption.

"Of special interest," says Johannes Flick, the main author of the work, "are the changes of the Born-Oppenheimer surfaces, which are used to characterize chemical reactions. We found that strong light-matter coupling induces novel reaction pathways." At the same time, the scientists investigated whether standard chemical reactions can be made more efficient by employing to the photons. To do so, they considered a simple model of charge transfer between two quantum systems. Such charge-transfer reactions are usually driven by a laser pulse. In this work, the reaction was assisted by a few photons in the optical cavity, which allowed for lower laser intensities.

"Our theoretical findings do not only help to better understand the behavior of atoms and molecules strongly coupled to photons in an optical cavity," says Johannes Flick, "but they also highlight the possibility to change chemical properties via photons." Next, the scientist want to apply their theoretical methods to more . The goal is to show that the current results are generally valid and that one can alter the chemical properties of all sorts of molecules via strong light-matter coupling.

Explore further: A quantum of light for materials science

More information: Atoms and Molecules in Cavities: From Weak to Strong Coupling in QED Chemistry. Johannes Flick, Michael Ruggenthaler, Heiko Appel and Angel Rubio, PNAS, Early Edition, dx.doi.org/10.1073/pnas.1615509114

Related Stories

A quantum of light for materials science

December 1, 2015

Computer simulations that predict the light-induced change in the physical and chemical properties of complex systems, molecules, nanostructures and solids usually ignore the quantum nature of light. Scientists of the Max-Planck ...

Controlling the thermodynamics of light

December 17, 2015

The concept of temperature is critical in describing many physical phenomena, such as the transition from one phase of matter to another. Turn the temperature knob and interesting things can happen. But other knobs might ...

Using light to move electrons and protons

October 17, 2016

(Phys.org)—In some chemical reactions both electrons and protons move together. When they transfer, they can move concertedly or in separate steps. Light-induced reactions of this sort are particularly relevant to biological ...

Recommended for you

Muons spin tales of undiscovered particles

April 20, 2018

Scientists at U.S. Department of Energy (DOE) national laboratories are collaborating to test a magnetic property of the muon. Their experiment could point to the existence of physics beyond our current understanding, including ...

Integrating optical components into existing chip designs

April 19, 2018

Two and a half years ago, a team of researchers led by groups at MIT, the University of California at Berkeley, and Boston University announced a milestone: the fabrication of a working microprocessor, built using only existing ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.