Ultrafast charge migration in molecules initiated by ionization and excitation

Exposing molecules to ultrashort pulses results typically in a coherent population of several and even many electronic states. This triggers ultrafast electron dynamics, which may lead to a redistribution of the charge even before the nuclei start to move and adjust – a process often referred to as charge migration [1,2]. The non-adiabatic coupling between the electronic and nuclear motion will eventually destroy the initial electronic coherence and trap the migrating charge. The time during which the electron coherence is maintained is an important parameter. This time can be used to modulate the charge migration process and thus predetermine the succeeding nuclear rearrangement in the molecule – the paradigm of the emerging field of attochemistry. In this talk, fully quantum simulations of ultrafast charge dynamics initiated by both ionization [3] and excitation [4] of polyatomic molecules will be presented. Examples of decoherence and revival of coherences will be shown, as well as a transfer of electronic coherence through conical intersections [4]. The possibility to trace these dynamics by attosecond transient-absorption spectroscopy [5] will be discussed.