Attosecond XUV-induced electron dynamics in molecules

Coherent light sources producing femtosecond and sub-femtosecond laser pulses come with the promise of achieving an actual control on excitation and ionization processes in atoms and molecules. New developments in high-harmonic generation techniques and free electron lasers (FEL) open the way to a real-time imaging of the ultrafast mechanisms that ultimately govern a large extent of charge transfer reactions of interest not only in biology, but also in novel technological applications [1,2]. Attosecond pump-probe spectroscopy has been successfully employed in a manifold of recent experiments pursuing to trace and manipulate molecular fragmentation paths [1]. Most of existing experiments available combine a single or a train of attosecond pulses in the VUV/XUV region to trigger molecular excitation or ionization, whose dynamics is then probed by the time-delayed interaction with an IR field. The ideally pursued scheme is that one using a second VUV/XUV pulse as a probe. This talk will discuss available theoretical methods for a reliable description of ultrafast electron dynamics in ionization processes [2]. The talk will present recent theoretical work to investigate the role of electron-electron correlation in the excitation and/or ionization of molecules when exposed to ultrashort XUV pulses [3-5]. We will then discuss how the coupling of the electronic motion with the nuclear degrees of freedom, in scenarios where they move at comparable time scales or they are tightly coupled, directly affecting the outcome of a reaction. For instance, ultrafast processes such that charge migration, which is predicted to occur prior nuclear rearrangement can be significantly altered when the nuclear degrees of freedom come into play [2,5]. [1] M. Nisoli, P. Decleva, F. Calegari, A. Palacios and F. Martín, Chemical Reviews 117, 10760 (2017) [2] A. Palacios and F. Martín, WIREs Computational Molecular Science 10, 1 (2020) [3] D. Jelovina, J. Feist, F. Martín and A. Palacios, New J. Phys. 20, 123004 (2018) [4] DIR. Boll, O. Fojón, C. W. McCurdy and A. Palacios, Phys. Rev. A 99, 023416 (2019) [5] J. Delgado, M. Lara-Astiaso, J. González-Vázquez, P. Decleva, A. Palacios and F. Martín, Faraday Discussions (https://doi.org/10.1039/D0FD00121J)