Project A7 - Ultrafast molecular stabilization mediated by electronic correlations

The ATTO group is part of the Collaborative Research Center SFB925 “Light induced dynamics and control of correlated quantum systems” from the Universität Hamburg. In particular, we contribute to the project entitled “Ultrafast molecular stabilization mediated by electronic correlations”, in collaboration with the group of Prof. Angel Rubio of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD).

When a molecule interacts with a single vacuum ultraviolet (VUV) photon, one electron can be promoted to the ionization continuum. This simple excitation process can be generally described using a single-particle approximation. This description fails when the excitation occurs at higher photon energies. In this case, electron correlation cannot be neglected, and multi-electronic effects must be considered. Understanding the role of multi-electronic processes in the photo-stability of a molecule is of fundamental interest for radiation physics, atmospheric chemistry and radiation-induced damage. Attosecond technology has been proven to be a powerful tool for the real time tracking of electronic processes and multi-electronic effects have been successfully measured in the time domain.

In this project electronic correlations are investigated in conjugated electron systems such as cyclic polycarbon molecules (nucleobases and PAHs) using the combination of attosecond extreme ultraviolet (XUV)/soft-x pulses and few-femtosecond UV/near-infrared (NIR) pulses. We focus on two correlation-driven processes: one one hand we aim to investigate charge migration, a purely electron process initiated by sudden ionization of a molecule and on the other hand we plan to study how correlation-based mechanisms such as shake-up can be used to implement a laser stabilization process in the dissociative molecule.

The main goals of this project are (i) to identify a possible control scheme for the charge migration process and (ii) to unravel a general mechanism for the laser-assisted stabilization of XUV photoionized molecules (relevant for astrochemistry, i.e. the origin of life in the universe) and thereby to establish new schemes, based on electron correlation, for the control of the molecular dissociation on a sub- to few femtosecond time scale.