# Berlin 2014 – wissenschaftliches Programm

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# MO: Fachverband Molekülphysik

## MO 13: Posters 3: Cold Molecules, Helium Nano Droplets, and Experimental Techniques

### MO 13.38: Poster

### Mittwoch, 19. März 2014, 16:30–18:30, Spree-Palais

**On the equivalence of spatial wave function and complete characterization of linear fragment momenta after many-body breakup** — •Peer C. Fechner and Hanspeter Helm — Physikalisches Institut, Albert-Ludwigs-Universität Freiburg

At the example of triatomic hydrogen, we discuss the equivalence of the spatial and momentum wave functions of a many-body system as they evolve after a fragmentation process (Phys.Chem.Chem.Phys., 2014, 16, 453).

State selected H_{3} molecules predissociate into the repulsive ground-state and undergo the 3-body decay *H*_{3} → *H*(1*s*)+*H*(1*s*)+*H*(1*s*). The correlated fragment momentum vectors of the hydrogen atoms are recorded in the laboratory frame in triple coincidence. Prudent design of the experiment permits to trace out the nuclear frame alignment in the laboratory (the photofragment angular distribution) to arrive at correlated fragment momentum vectors in the center-of-mass. Accumulation of typically ∼ 10^{4} such observations yields a probability map of final momentum configurations, equivalent to the modulus square of the momentum wave function long after the decay. Comparison with the known initial spatial wave function suggests a close relationship of spatial and momentum wave function, which is predicted by theory in the form of the *imaging theorem*.
We conclude that prudent imaging of many-body fragmentation provides a laboratory view of the squared many-body wave function at a spatial scale of molecular dimensions at which fragments exit into the realm of independent free particles.