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Controlling the interactions between atoms with external fields opened up new branches in physics ranging from strongly correlated atomic systems to ideal Bose and Fermi gases and Efimov physics. Such control usually prepares samples that are stationary or evolve adiabatically in time. On the other hand, in molecular physics external ultrashort laser fields are employed to create anisotropic potentials that launch ultrafast rotational wave packets and align molecules in free space. Here we combine these two regimes of ultrafast times and low energies. We apply a short laser pulse to the helium dimer, a weakly bound and highly delocalized single bound state quantum system. The laser field locally tunes the interaction between two helium atoms, imparting an angular momentum of $2hbar$ and evoking an initially confined dissociative wave packet. We record a movie of the density and phase of this wave packet as it evolves from the inside out. At large internuclear distances, where the interaction between the two helium atoms is negligible, the wave packet is essentially free. This work paves the way for future tomography of wave packet dynamics and provides the technique for studying exotic and otherwise hardly accessible quantum systems such as halo and Efimov states.
We show that a single photon can ionize the two helium atoms of the helium dimer in a distance up to 10 {deg}A. The energy sharing among the electrons, the angular distributions of the ions and electrons as well as comparison with electron impact dat
Using synchrotron radiation we simultaneously ionize and excite one helium atom of a helium dimer (He_2) in a shakeup process. The populated states of the dimer ion (i.e. He^[*+](n = 2; 3)-He) are found to deexcite via interatomic coulombic decay. Th
We report the first experimental evidence of spontaneous electron emission from a homonuclear dimer anion through direct measurements of $rm{Ag}_2^- rightarrow rm{Ag}_2 + rm{e}^-$ decays on milliseconds and seconds time scales. This observation is ve
The infrared spectrum of the cross-shaped van der Waals complex N2O-CS2 is observed in the region of the N2O nu1 fundamental band (~2220 cm-1) using a tuneable diode laser to probe a pulsed supersonic slit jet expansion. Both 14N- and 15N-substituted
We report on the production and study of stable, highly charged droplets of superfluid helium. Using a novel experimental setup we produce neutral beams of liquid helium nanodroplets containing millions of atoms or more that can be ionized by electro