Fig. 4. Possible charge and molecular dynamics induced by the terahertz electric field.

a Mott insulator state, b polar CO state induced by the terahertz electric field, and c polar CO state stabilized by molecular displacements decreasing the dimerization. The blue and red curved arrows indicate the intradimer charge transfers and the green arrows indicate the molecular displacements. The polar CO state is stabilized by the decrease of the dimerization only in κ-Cl.