title: Imaging the structure of the trimer systems (4)He3 and (3)He(4)He2.
abstract: Helium shows fascinating quantum phenomena unseen in any other element. In its liquid phase, it is the only known superfluid. The smallest aggregates of helium, the dimer (He2) and the trimer (He3) are, in their predicted structure, unique natural quantum objects. While one might intuitively expect the structure of (4)He3 to be an equilateral triangle, a manifold of predictions on its shape have yielded an ongoing dispute for more than 20 years. These predictions range from (4)He3 being mainly linear to being mainly an equilateral triangle. Here we show experimental images of the wave functions of (4)He3 and (3)He(4)He2 obtained by Coulomb explosion imaging of mass-selected clusters. We propose that (4)He3 is a structureless random cloud and that (3)He(4)He2 exists as a quantum halo state.
authors.affiliation: Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, 60438 Frankfurt, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Voigtsberger
authors.affiliation: Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, 60438 Frankfurt, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Zeller
authors.affiliation: Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, 60438 Frankfurt, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Becht
authors.affiliation: Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, 60438 Frankfurt, Germany.
authors.forename: N
authors.initials: N
authors.lastname: Neumann
authors.affiliation: Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, 60438 Frankfurt, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Sturm
authors.affiliation: Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, 60438 Frankfurt, Germany.
authors.forename: H-K
authors.initials: HK
authors.lastname: Kim
authors.affiliation: Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, 60438 Frankfurt, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Waitz
authors.affiliation: Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, 60438 Frankfurt, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Trinter
authors.affiliation: Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, 60438 Frankfurt, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Kunitski
authors.affiliation: Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, 60438 Frankfurt, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Kalinin
authors.affiliation: State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China.
authors.forename: J
authors.initials: J
authors.lastname: Wu
authors.affiliation: Department of Molecular Physics, Fritz-Haber-Institut der Max-Planck-Gesellschaft, 14195 Berlin, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Schöllkopf
authors.affiliation: Dipartimento di Scienza e Alta Tecnologia, University of Insubria, 22100 Como, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Bressanini
authors.affiliation: Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, 60438 Frankfurt, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Czasch
authors.affiliation: Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, 60438 Frankfurt, Germany.
authors.forename: J B
authors.initials: JB
authors.lastname: Williams
authors.affiliation: Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, 60438 Frankfurt, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Ullmann-Pfleger
authors.affiliation: Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, 60438 Frankfurt, Germany.
authors.forename: L Ph H
authors.initials: LP
authors.lastname: Schmidt
authors.affiliation: Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, 60438 Frankfurt, Germany.
authors.forename: M S
authors.initials: MS
authors.lastname: Schöffler
authors.affiliation: Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, 60438 Frankfurt, Germany.
authors.forename: R E
authors.initials: RE
authors.lastname: Grisenti
authors.affiliation: Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, 60438 Frankfurt, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Jahnke
authors.affiliation: Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, 60438 Frankfurt, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Dörner