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arXiv · 2607.00598

Nondipole Contributions to Attosecond Chiral Photoionization Asymmetries

Zheming Zhou·Yang Li·Yueming Zhou·Peixiang Lu
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Abstract

Photoelectron circular dichroism (PECD) reads molecular chirality from forward-backward asymmetries in photoelectron emission, but the same observable can also contain non-dipole contributions from photon momentum transfer. Here we show that such contributions can reshape attosecond PECD measurements in both one- and two-photon ionization of chiral molecules. Calculations beyond the dipole approximation, interpreted with perturbation theory, reveal that non-dipole effects modify not only the magnitude but also the phase of the emitted electron wave packet. In two-photon interferometry, pathway interference amplifies the non-dipole response and can reverse the apparent chiral asymmetry. We further identify a practical separation principle: the non-dipole component is insensitive to enantiomeric handedness and can therefore be obtained from a racemic mixture. Subtracting this background isolates the purely chirality-induced asymmetry, enabling more accurate measurements of chiral electron dynamics.

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Zheming Zhou, Yang Li, Yueming Zhou, Peixiang Lu. 2026-07-01. Nondipole Contributions to Attosecond Chiral Photoionization Asymmetries. https://arxiv.org/abs/2607.00598

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