Twisted-Driven Photoionization of Aligned Chiral Molecules: Signatures of Circular and Helical Dichroism

The study of twisted light interacting with chiral molecules offers a major opportunity and challenge for probing molecular handedness using structured light fields. Through a detailed theoretical investigation of twisted-photon-induced single ionization in aligned chiral methyloxirane molecules, we consider two distinct scenarios: in ensembles of aligned molecules randomly distributed across the transverse beam profile, photon-energy and angle-resolved spectra show clear circular dichroism but no sensitivity to the light's total angular momentum (TAM), indicating that this dichroic signal reflects the combined effects of molecular chirality and molecular alignment; whereas for a single molecule or mesoscopic target at a fixed impact parameter, ionization cross sections gain sensitivity to both TAM and molecular chirality, revealing helical dichroism for forward-emitted photoelectrons and showing that spatially localized interactions allow explicit coupling between the full angular momentum of the photon and molecular chirality, thereby harnessing the spatial structure of light for chiral sensing.