Probing electron localization during molecular dissociation by femtosecond strong-field ion momentum spectroscopy

The study of molecular valence electron dynamics and their coupling with nuclear motion is one of the frontiers of ultrafast physics and ultrafast chemistry. With time-resolved strong-field ion momentum spectroscopy, we study electron valence and nucleus wavepacket evolution on a femtosecond timescale. Two orientation-dependent bond-breaks of N 2 O molecules from the same electronic state are studied, and the influence of orbital hybridization and polarization effect during molecular breaking is analyzed based on the measured time-resolved asymmetric Pzsum distributions, allowing a visual representation of electron localization during the dissociation of molecules into ions and atoms. Comparison of experimental and theoretical results on orientation-dependent dissociation dynamics allows us to understand how nuclear motions evolve during fragmentation and to control ultrafast molecular reactions.