Attosecond control and tracing of wavepacket dynamics in excited states in polyatomic molecules

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Molecular processes are driven by nuclear and electronic motion. Many successful examples to observe and control the nuclear degrees of freedom for molecular systems with increasing complexity have been reported over the last decades. In the past few years few-cycle pulses and the possibility to tailor their waveform paved the way to observe and control even the fast motion of electrons. Experiments as well as theory so far concentrated on small diatomic molecules and due to the nature of the light fields (strong laser fields) on their dynamics in ionic states. In our proposal, we aim at investigating, in a combined experimental and theoretical approach, the interaction of pulses with tailored fields with more complex molecules. Specifically, we want to follow and control the induced dynamics in the neutral states, where chemistry takes place mostly. The selected systems, like the nucleobases uracil or the proton-transfer system 3-aminoacrolein, offer a variety of nuclear and electronic degrees of freedom, which we aim to control simultaneously by tailoring the electric-field waveform with the phase as the prominent control knob. In order to carry out the experiments we aim for an UV excitation, that resonantly populates the excited states . A time-delayed control pulse with tailored field couples electronic and/or nuclear degrees of freedom for steering the evolution of the molecular processes. The control will be monitored, using a third pulse in the extreme ultraviolet, via Coulomb explosion or photoelectron spectroscopy. The theoretical investigations are performed to analyze and understand the underlying processes and to give guidance for the experimental parameters. To this extend we will expand our own designed program code that treats the quantum dynamics of nuclear and electron motion simultaneously from diatomics to polyatomic systems. This will allow us to explore the phase control on the nuclear- as well as on the electronic wavepacket and to develop strategies to make the control most efficient.The results from experiment and theory together will lead to a detailed understanding of the nuclear and electron dynamics in complex molecules, the natural lifetime of electronic coherence and possibilities to steer reactions via phase control.