  The recently introduced synthetic chiral light [D. Ayuso et al, Nat. Photon.
13, 866-871 (2019)] has opened up new opportunities for ultrafast and highly
efficient imaging and control of chiral matter. Here we show that the giant
enantio-sensitivity enabled by such light could be exploited to probe chiral
nuclear rearrangements during chemical reactions in an highly enantio-sensitive
manner. Using a state-of-the-art implementation of time-dependent density
functional theory, we explore how the nonlinear response of the prototypical
chiral molecule H2O2 changes as a function of its dihedral angle, which defines
its handedness. The macroscopic intensity emitted from randomly oriented
molecules at even harmonic frequencies (of the fundamental) depends strongly on
this nuclear coordinate. Because of the ultrafast nature of such nonlinear
interactions, the direct mapping between chiral dichroism and nuclear geometry
provides a way to probe chiral nuclear dynamics at their natural time scales.
Our work paves the way for ultrafast and highly efficient imaging of
enantio-sensitive dynamics in more complex chiral systems, including
biologically relevant molecules.
