In a study entitled “Near-complete chiral selection in rotation quantum states” published in Nature communicationThe Controlled Molecules Group of the Molecular Physics Department of the Fritz Haber Institute has made a significant leap forward in the field of chiral molecules. The team led by Dr. Sandra Eibenberger-Arias achieved a nearly complete separation of the quantum states of these essential building blocks of life.

This discovery challenges previous assumptions about the practical limits of quantum state control of chiral molecules and paves the way for new research directions in molecular physics and beyond.

Chiral molecules that exist as two non-superimposable mirror-image versions, called enantiomers, similar to our left and right hands, are fundamental to the fabric of life. The ability to control these molecules and their quantum states has profound implications, from spatially separating enantiomers in the gas phase to testing hypotheses about the origins of life’s homochirality – the preference for one mirror image over the other in biological systems.

Until now, scientists believed that perfect control of the quantum states of these molecules was theoretically possible but practically unattainable. However, the team at the Fritz Haber Institute has proven the opposite. By creating almost ideal experimental conditions, they were able to show that 96 percent purity of the quantum state of one enantiomer (one of the two mirror images) is achievable, while the other is only 4 percent pure. This brings them significantly closer to the goal of 100 percent selectivity.

This breakthrough was made possible by using tailored microwave fields in combination with ultraviolet radiation, which allows unprecedented control over the molecules. In the experiment, a beam of molecules whose rotational motions are largely suppressed (cooled to a rotational temperature of about 1 degree above absolute zero) traverses three interaction regions where it is exposed to resonant UV and microwave radiation. As a result, selected rotational quantum states contain almost exclusively the selected enantiomer of a chiral molecule – a significant advance in molecular beam experiments.

The new experiment opens up new possibilities for studying fundamental physical and chemical effects involving chiral molecules. The team’s method offers a new approach for studying parity violation in chiral molecules – a phenomenon that has been predicted theoretically but not yet observed experimentally. This could have profound implications for our understanding of the fundamental (a)symmetries of the universe.

In essence, this study demonstrates that nearly complete enantiomer-specific state transfer is possible and that this method can be applied to the vast majority of chiral molecules. This discovery is expected to open up important new possibilities in molecular physics, including new research avenues and potential applications.