Coherent ring currents in chiral aromatic molecules induced by linearly polarized UV laser pulses

A fundamental principle of generation of ultrafast coherent ring currents and the control in photo-induced aromatic molecules is presented. The system evolves from clockwise to counterclockwise rotations repeatedly. The second key for obtaining a unidirectional ring current is to delete rotations in the opposite direction. The system is returned to the ground state by the dump pulse before reverse rotation starts. The principle is a creation of electronic coherence of quasi-degenerate states of by a linearly polarized UV pulses. Ultrafast coherent ring currents and current-induced magnetic fluxes in chiral molecular systems have wide applicability toward realization of organic devices for ultrafast switching.