We experimentally obtained a direct image of the nuclear wave functions of {H_2}^+ by dissociating the molecule via electron attachment and determining the vibrational state using the COLTRIMS technique. Our experiment visualizes the nodal structure
of different vibrational states. We compare our results to the widely used reflection approximation and to quantum simulations and discuss the limits of position measurements in molecules imposed by the uncertainty principle.
We have measured the molecular frame angular distributions of photoelectrons emitted from the Carbon K shell of fixed-in-space CO molecules for the case of simultaneous excitation of the remaining molecular ion. Normal and conjugate shake up states a
re observed. Photo electrons belonging to normal Sigma -satellite lines show an angular distribution resembling that observed for the main photoline at the same electron energy. Surprisingly a similar shape is found for conjugate shake up states with Pi -symmetry. In our data we identify shake rather than electron scattering (PEVE) as the mechanism producing the conjugate lines. The angular distributions clearly show the presence of a Sigma -shape resonance for all of the satellite lines.
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
a for helium atoms suggest a knock-off type double ionization process. The Coulomb explosion imaging of He_2 provides a direct view of the nuclear wave function of this by far most extended and most diffuse of all naturally existing molecules.
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
is leads to the emission of a second electron from the neutral site and a subsequent coulomb explosion. In this letter we present a measurement of the momenta of fragments that are created during this reaction. The electron energy distribution and the kinetic energy release of the two He^+ ions show pronounced oscillations which we attribute to the structure of the vibrational wave function of the dimer ion.
We used Cold Target Recoil Ion Momentum Spectroscopy (COLTRIMS) to investigate the decay of Ne$_2$ after K-shell photoionization. The breakup into Ne$^{1+}$ / Ne$^{2+}$ shows interatomic Coulombic decay (ICD) occurring after a preceding atomic Auger
decay. The molecular frame angular distributions of the photoelectron and the ICD electron show distinct, asymmetric features, which imply localization of the K-vacancy created at one of the two atomic sites of the Ne$_2$ and an emission of the ICD electron from a localized site. The experimental results are supported by calculations in frozen core Hartree-Fock approach.
