Dynamics of Photochemical Reactions via Conical Intersections

Conical intersections are important pathways for many photochemical reactions leading to fast radiation-less decay in photo-excited molecules, which is currently intensively studied. In the framework of a trilateral cooperation with Israeli and Palestinian research groups we investigate the quantum dynamics of photochemical reactions, in particular photoisomerization processes, via conical intersections. In photo-excited system, the deactivation through a conical intersection often competes with other reaction pathways like internal torsion or isomerization. One of our goals is to design laser pulses which steer the system to a desired outcome, e.g. to induce torsion and avoid ultrafast deactivation. One of our main activities is the investigation of molecular symmetry effects in photo-chemical reactions. Due to its symmetry, a molecule can have several equivalent conical intersections at symmetric configurations. We were able to show how molecular symmetry imposes constraints on the conical intersections and the related non-adiabatic coupling terms which have consequences for ab initio quantum chemical calculations of the coupling elements and quantum dynamical simulations of nuclear dynamics on coupled electronic states. Currently we are exploring further prospects and applications for the combination of quantum chemistry and quantum dynamics of photo-excited systems with molecular symmetry.

This project is carried out in cooperation with Y. Haas and S. Zilberg, Hebrew University of Jerusalem (Phase localization of conical intersections) and O. Deeb, Al-Quds University (Quantum Chemistry).