Fig. 2: Enantio-sensitive orientation by photoionization.

Relative orientations of the molecular vectors \({\hat{{{{{{{{\bf{e}}}}}}}}}}_{{{{{{{{\rm{B}}}}}}}}}\) and \({{{{{{{{\bf{P}}}}}}}}}_{ij}^{+}\) for opposite molecular orientations and opposite enantiomers for k = 0.2 a.u. and a superposition of \(\left\vert i\right\rangle =\left\vert {{{{{{{\rm{LUMO}}}}}}}}\right\rangle\) and \(\left\vert j\right\rangle =\left\vert {{{{{{{\rm{LUMO}}}}}}}}+1\right\rangle\) in propylene oxide. Panels (a) and (b) represent oppositely oriented right enantiomers. Panels (c) and (d) represent oppositely oriented left enantiomers. The red circular arrow shows the rotation direction of the circularly polarized field. The green circular arrows show the circular current in the excited states right before ionization takes place. Photoionization rates are higher for orientations (a) and (c) than for (b) and (d) because ionization is more effective when the electronic current (circular green arrow fixed to \({{{{{{{{\bf{P}}}}}}}}}_{ij}^{+}\)) and the electric field rotate in the same direction. This difference in photoionization rates causes enantio-sensitive orientation.