Laser-field-induced surface-hopping method for the simulation and control of ultrafast photodynamics

We present the semiclassical laser-field-induced surface-hopping method for the simulation and control of coupled electron-nuclear dynamics in complex molecular systems including all degrees of freedom. Our approach is based on the Wigner representation of quantum mechanics. The combination of the molecular dynamics ``on the fly'' employing quantum initial conditions with the surface-hopping procedure allows for the treatment of the electronic transitions induced by the laser field. Our semiclassical approach reproduced accurately exact quantum dynamics in a two-electronic-state model system. We demonstrate the scope of our method on the example of the optimal pump-dump control of the trans-cis isomerization of a prototypical Schiff base molecular switch. Our results show that selective photochemistry can be achieved by shaped laser pulses which open new dynamical pathways by suppressing the isomerization through the conical intersections between electronic states.