Nuclear–Electron Correlation Effects and Their Photoelectron Imprint in Molecular XUV Ionisation

Abstract

The ionisation of molecules by attosecond XUV pulses is accompanied by complex correlated dynamics, such as the creation of coherent electron wave packets in the parent ion, their interplay with nuclear wave packets, and a correlated photoelectron moving in a multi-centred potential. Additionally, these processes are influenced by the dynamics prior to and during the ionisation. To fully understand and subsequently control the ionisation process on different time scales, a profound understanding of electron and nuclear correlation is needed. Here, we investigate the effect of nuclear–electron correlation in a correlated two-electron and one-nucleus quantum model system. Solving the time-dependent Schrödinger equation allows to monitor the correlation impact pre, during, and post-XUV ionisation. We show how an initial nuclear wave packet displaced from equilibrium influences the post-ionisation dynamics by means of momentum conservation between the target and parent ion, whilst the attosecond electron population remains largely unaffected. We calculate time-resolved photoelectron spectra and their asymmetries and demonstrate how the coupled electron–nuclear dynamics are imprinted on top of electron–electron correlation on the photoelectron properties. Finally, our findings give guidelines towards when correlation resulting effects have to be incorporated and in which instances the exact correlation treatment can be neglected.

Attosecond ionization dynamics of modulated, few-cycle XUV pulses

“…It is yet to be addressed how temporal dynamic interference effects are present for these kind of pulses and have to be thoughtfully dissected from the CEP-and intensitydependent effects unraveled in this work. Moreover, it has been shown recently that electronic and nuclear correlation lead to asymmetries in the PES during XUV ionization [56], therefore, the interplay with the asymmetry from attosecond pulses reported here would be of future interest.…”