Abstract
The development of efficient techniques to distinguish mirror images of chiral molecules (enantiomers) is very important in both chemistry and physics. Enantiomers share most molecular properties except, for instance, the absorption of circularly polarized light. Enantiomer purification is therefore a challenging task that requires specialized equipment. Strong coupling between quantized fields and matter (e.g., in optical cavities) is a promising technique to modify molecular processes in a noninvasive way. The modulation of molecular properties is achieved by changing the field characteristics. In this work, we investigate whether strong coupling to circularly polarized electromagnetic fields is a viable way to discriminate chiral molecules. To this end, we develop a nonperturbative framework to calculate the behavior of molecules in chiral cavities. We show that in this setting the enantiomers have different energies—that is, one is more stable than the other. The field-induced energy differences are also shown to give rise to enantiospecific signatures in rotational spectra.
- Received 5 September 2022
- Revised 3 February 2023
- Accepted 30 May 2023
DOI:https://doi.org/10.1103/PhysRevX.13.031002
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.
Published by the American Physical Society
Physics Subject Headings (PhySH)
Popular Summary
Chiral molecules are ubiquitous in chemistry and biology. These are molecules whose mirror images cannot be superimposed on each other. All amino acids in our bodies, for example, are chiral, as are most medical drugs. In the case of drugs, only one of the two chiral forms has a healing effect; the other could be inactive or even toxic. The ability to distinguish between pairs of chiral molecules—known as enantiomers—is therefore important but difficult, given that the two forms share nearly all physical properties. Here, we theoretically investigate whether strong coupling to circularly polarized electromagnetic fields is a viable way to differentiate between two enantiomers.
We develop a nonperturbative framework to calculate the behavior of molecules in chiral optical cavities. We show that in this setting the enantiomers have different energies—that is, one is more stable than the other. The field-induced energy differences are also shown to give rise to enantiospecific signatures in rotational spectra.
This work represents the first evidence of field-induced energy differences of the enantiomer ground states through strong coupling.
