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Abstract

In this work the laser-induced ionization of atoms and simple molecules is experimentally investigated by using a Reaction Microscope and sculpted laser pulses. The Reaction Microscope allows to distinguish different ionization channels with the ion-electron coincidence technique. The sculpted laser pulses, which are realized by superposition of two laser pulses with different colors and adjustable relative phase, play a key role in controlling the electronic wavepacket with high temporal resolution. With these two methods, phase-controllable strong-field ionization of Ar and N₂ is studied and electrons emitted from single ionization of Ar and N₂ are compared. Moreover, channel-selective electron emission is investigated for the fundamental molecular case of H₂. A significant difference in the low-energy photoelectron yield between bound and dissociative ionization channel is observed, proving the Born-Oppenheimer-based twostep process is not complete. Finally, this observation is understood as the population and subsequent decay of autoionizing states by further investigations with the two-color laser pulses.