Ultrafast Dynamics in Donor-Acceptor Prototype Molecules by XUV-IR Attosecond Spectroscopy

Photoinduced electron transfer and charge transfer are processes at the basis of core technologies aiming, for example, at effective conversion of solar energy into electrical energy. A complete understanding of these processes requires real-time imaging of the electronic-nuclear motion, taking place on the few-femtosecond time scales [1]. Here we investigate, by attosecond spectroscopy, the ultrafast dynamics following photoionization in nitroanilines, the simplest donor-acceptor system. We explore three systems with different functionalization of the push-pull groups (4-nitroaniline, 4-NA; 3-nitroaniline, 3-NA; N,N-Dimethyl-4-nitroaniline, nd-NA; chemical structures shown in Fig. 1). Our results, supported by photo-electron photo-ion coincidence energy-resolved (PEPICO) measurements and quantum simulations, show that the observed ultrafast dynamics are correlated to the wave-packet spreading in the excited states of the cation.