  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.
