Speaker
Description
Chiral molecules play a vital role in pharmaceuticals, materials science, and agrochemicals, as their mirror-image forms (enantiomers) can exhibit different biological and chemical properties. Distinguishing between these enantiomers is challenging, driving research into advanced light-matter interaction techniques, including nonlinear methods based on electric dipole interactions, which can enhance chiroptical sensitivity by orders of magnitude and introduce concepts like local chirality [1]. For instance, locally chiral Lissajous figures of synthetic chiral light can generate strong enantio-sensitive signals in high-harmonic generation [2].
Inspired by this, we examine the interplay between two locally chiral structures: the induced polarization vector of chiral electron currents, and the rotational trajectory of a molecule, both driven by locally chiral fields. Using a pump-probe setup, we analyse how the chiral rotational dynamics affect photoionization and photoexcitation, finding signatures of the interferences between chiral motions evolving on different time scales. This analysis has been conducted for both an achiral molecule and a chiral molecule using chiral hydrogenic electronic states [3] as a model of chiral electronic density. We demonstrate that even achiral spherical top molecules can exhibit chiral rotational trajectories in space (analogous to Lissajous figures of synthetic chiral light) under controlled excitation. Furthermore, by exploring the ultrafast enantio-sensitive electronic response in rotating chiral molecules, we identify new efficient enantio-sensitive observables, such as transient absorption and photoelectron circular dichroism of chiral rotors.
FIG. 1: Excitation scheme induced by the probe pulse, acting on molecular state as product of chiral rotational wavepacket (left ket in the product) and chiral electronic state (right ket in the product).
Acknowledgement
We gratefully acknowledge ERC-2021-AdG project ULISSES, grant agreement No.101054696
References
[1] D. Ayuso, A. F. Ordonez, and O. Smirnova, Phys. Chem. Chem. Phys. 24, 26962 (2022).
[2] D. Ayuso, et al, Nat. Photonics 13, 866 (2019).
[3] A. F. Ordonez, and O. Smirnova, Phys. Rev. A 99, 043416 (2019).
