Rotational vibrations directional motion control

Relation (6.40) represents a dynamical mapping which is mediated by Hamilton s equations of motion in the upper state and ultimately by the forces —dV/dR and —dV/dr and the torque —dV/d y. The energy dependence is mainly determined by the slope dV/dR of the potential in the direction of the dissociation path while dV/dr and dV/d y control the vibrational and rotational state distribution of the fragment. 

Nevertheless, the coupled vibrational-rotational-field dynamics has not been investigated in much detail. An exception is the work of Hornung and de Vivie-Riedle [204], who studied this interplay in connection with optimal control theory (OCT) [17, 42]. With respect to experiment, the new technique of polarization shaping [205-208] is directly connected to the angular motion. 

The results presented in this chapter show that the use of proper effective models, in combination with calculations based on the exact vibrational Hamiltonian, constitutes a promising approach to study the laser driven vibrational dynamics of polyatomic molecules. In this context, the MCTDH method is an invaluable tool as it allows to compute the laser driven dynamics of polyatomic molecules with a high accuracy. However, our models still contain simplifications that prevent a direct comparison of our results with potential experiments. First, the rotational motion of the molecule was not explicitly described in the present work. The inclusion of the rotation in the description of the dynamics of the molecule is expected to be important in several ways. First, even at low energies, the inclusion of the rotational structure would result in a more complicated system with different selection rules. In addition, the orientation of the molecule with respect to the laser field polarization would make the control less efficient because of the rotational averaging of the laser-molecule interaction and the possible existence of competing processes. On the other hand, the combination of the laser control of the molecular alignment/orientation with the vibrational control proposed in this work could allow for a more complete control of the dynamics of the molecule. A second simplification of our models concerns the initial state chosen for the simulations. We have considered a molecule in a localized coherent superposition of vibrational eigenstates but we have not studied the preparation of this state. We note here that a control scheme for the localiza-... 

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