Theory of Magneto-electric Dynamics in Charge Separation

A time dependent theory of magneto-electric nonlinearities at the molecular level is presented, with an emphasis on rectification. Magneto-electric nonlinearities are interactions that involve both the electric and magnetic fields of light. Recent experimental evidence indicates that these interactions are mediated by the transfer of orbital angular momentum to molecular rotations through the action of optical torque at low intensities. By including torque dynamics in an otherwise classical electron oscillator model, a quantitative model of the interactions can be developed to include temporal evolution. The solutions to the equations of motion clearly show the role of both a parametric resonance and torque dynamics in driving the magneto-electric nonlinearities. Simulations are directly compared to experimental measurements of magneto-electric rectification to examine the accuracy of the model.