Spectroscopy and control of strongly entangled electronic and nuclear motions in molecules: theoretical aspects

The primary steps of photoinduced electron and proton transfer are the fastest processes in chemical systems and occur on the time scale of attoseconds to 10 fs. This project will develop new theoretical tools for the description and interpretation of the new measurements made possible by attosecond pulses at fixed carrier frequencies and tunable few-fs pulses in the UV and will guide the experiments in the research areas C.1 and C.2. The criteria for the selected molecular systems are their strongly entangled electronic-nuclear dynamics and the wealth of functionalities derived therefrom.

Ab initio electronic-structure calculations will be performed for ground and excited states of polyatomic systems, e. g., donor-bridge-acceptor systems, DNA bases, oligomers, and peptides. They are indispensable for the experimental projects and for the subsequent quantum dynamical calculations and the theoretical description of the femto(/atto)second nonlinear spectroscopy. The available methods for the solution of the time-dependent Schrödinger equation or reduced density-matrix equations of motion will be further developed to cope with the strongly coupled electronic and nuclear motions induced by multiple conical intersections. The theory of strong field interaction will be extended to provide the description of novel types of experiments like UV pump, IR probe (C.2.3) or femtosecond time-resolved photoelectron spectroscopy (C.2.4).