Laser-Induced nonadiabatic processes in molecular systems: Theory and applications

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In this project we continue our former research work on the field of laser-induced nonadiabatic processes. It is well known that conical intersections (CIs) between electronic potential energy surfaces play an important role in nonadiabatic molecular processes. In CI situations the electronic states are coupled by the nuclear motion and the energy exchange between the electrons and the nuclei becomes significant. For polyatomic molecules, CIs are ubiquitous. As a consequence of the well-known "noncrossing rule", CIs cannot be formed in field-free diatomics. However, by applying external fields, CI can be created even in diatomics. In this situation the laser light induces CIs which couple the electronic states and the internal rotation and vibrational motions. It was pointed out in our former works, that such light-induced conical intersections (LICIs) have very strong impact on various dynamical properties (like molecular spectra, molecular alignment or photodissociation probability) of diatomic molecules. Our research programme includes the following three major topics: (I) Controlling molecular dynamical processes by LICIs using chirped laser pulses. We plan to design the chirp such as to achieve a desired outcome of the photodissociation process of D2+. (II) Demonstration of the impact of the laser-induced conical intersections on the absorption spectra of molecules. We plan to investigate how the usual Franck-Condon approximation breaks down in the presence of LICIs. (III) Investigation of the impact of LICIs in triatomic systems. In particular, we plan to study the effect of the LICI formed between the ground (X) and the Hartley (B) states of the ozone molecule.