Probing molecular chirality via laser-induced electronic fluxes

Abstract: Chirality is ubiquitous in nature and of fundamental importance in science. The present work focuses on understanding the conditions required to modify the chirality during ultrafast electronic motion by bringing enantiomers out-of-equilibrium. Different kinds of ultrashort linearly-polarised laser pulses are used to drive an ultrafast charge migration process by the excitation of a small number of low-lying excited states from the ground electronic state of S- and R-epoxypropane. Control over chiral electron dynamics is achieved by choosing the different orientations of the linearly polarised pulse. We find that chirality breaking electric fields are only possible in oriented molecules, and that charge migration remains chiral when the polarisation of the field lies in the mirror plane defining the enantiomer pair, or when it is strictly perpendicular to it. Ultimately, the presence or the absence of a mirror symmetry for the enantiomer pair in the external field determines the chiral properties of the charge migration process.