Probing Electronic Symmetry Reduction during Charge Migration via Time-Resolved X-Ray Diffraction

Chemphyschem. 2023 Jan 17;24(2):e202200463. doi: 10.1002/cphc.202200463. Epub 2022 Nov 11.

Abstract

The present work focuses on probing ultrafast charge migration after symmetry-breaking excitation using ultrashort laser pulses. LiCN is chosen as prototypical system because it can be oriented in the laboratory frame and it possesses optically-accessible charge transfer states at low energies. The charge migration is simulated within the hybrid time-dependent density functional theory/configuration interaction framework. Time-resolved electronic current densities and simulated time-resolved x-ray diffraction signals are used to unravel the mechanism of charge migration. Our simulations demonstrate that specific choices of laser polarization lead to a control over the symmetry of the induced charge migration. Moreover, time-resolved x-ray diffraction signals are shown to encode transient symmetry reduction at intermediate times.

Keywords: current density; electron dynamics; symmetry Breaking; time-resolved x-ray diffraction.