STSM by Sandra Gomez,  Complutense University of Madrid (ES) with Volker Engel Institut für Physikalische und Theoretische Chemie der Universität Würzburg (DE)
On November 23rd, 2014 (5 days)logo

Strong field decoupling of nuclear dynamics

The interaction of molecules with strong laser fields produces molecular dynamics much more complicated than in the presence of weak fields. The solution for structureless two-level systems in a single frequency field is known as Rabi solution and the population of states oscillates at the Rabi frequency, known as Rabi oscillations or Rabi floppings.
When this system is replaced by two electronic states with dependance on nuclear coordinates, the Rabi oscillations decay on time while the nuclei are moving due to a dephasing that damps electronic coherences.
The goal of our collaboration is to minimize these effects by decoupling as much as possible the nuclear motion.

During the short visit we discussed possible models where these effects could be observed, we generated the potential energy curves of some diatomic molecules (Na2 and NaI) and we started to study how to analyze the dynamics using hamiltonians of coupled electron-nuclear motion (beyond Born-Oppenheimer approximation).
Due to the short time availiable, only the transition between ground and first excited state of Na2 molecule was studied at different amplitudes of the laser field (continuous wave laser).
We plan to extend these results to systems with other decoherence processes, as the NaI predissociation and to control of coupled nuclear and electronic degrees of freedom.

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