Berlin 2001 – scientific programme
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MO: Molekülphysik
MO 8: Posters Thursday: Dissociation and other Collision Processes
MO 8.2: Poster
Thursday, April 5, 2001, 12:30–15:00, AT3
Molecular binding angle distributions from fast-beam Coulomb explosion imaging: The case of CH2+ — •Lutz Lammich1, Lars Knoll1, Holger Kreckel1, Sven Krohn1,2, Jacob Levin1, Dirk Schwalm1, Zeev Vager2, Roland Wester1, Peter Witte1, Andreas Wolf1, and Daniel Zajfman2 — 1Max-Planck-Institut für Kernphysik, Heidelberg, Germany — 2Weizmann Institue of Science, Rehovot, Israel
In contrast to conventional spectroscopic approaches, the Coulomb explosion imaging technique allows a direct view on the nuclear configuration density distributions of small molecular ions. In this technique, a MeV beam of molecular ions is directed to a very thin foil where the valence and in general also several core electrons are stripped off. The repulsive Coulomb potential acting between the remaining ionic cores then causes a rapid fragmentation of the molecules. By measuring the resulting asymptotic velocities of a large number of molecules information on the probability distribution of the spatial nuclear configuration in the incoming molecules can be extracted. — In this contribution we focus on quasilinear heteroatomic ions, for which bond-angle distributions were determined by fast-beam Coulomb explosion imaging and compared to theoretical predictions for the associated bending modes of vibrational excitation. For these molecules the theoretical treatment becomes difficult as rotational and vibrational modes cannot be seperated completely. A special interest lies in the study of CH2+, where the double degeneracy of the electronic ground state is removed by vibronic coupling (Renner-Teller effect). Supported by GIF, DIP(BMBF) and MINERVA.