Stuttgart 2012 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 14: Poster 2: Biomolecules, Electronic Spectroscopy, Experimental Techniques, Quantum Chemistry, Various Topics
MO 14.29: Poster
Mittwoch, 14. März 2012, 16:30–19:00, Poster.IV
Experimental imaging of non-adiabatic coupling in a triatomic molecule — •Peer Cornelis Fechner, Kai Mozer, and Hanspeter Helm — Physikalisches Institut, Albert-Ludwigs-Universität Freiburg
Due to its simple structure, the neutral triatomic hydrogen molecules H3 and D3 are model-systems for the intramolecular dynamics in polyatomic molecules. We find these dynamic features encoded in correlations of the atom-momentum-vectors emerging from 3-body-decay of state selected molecules, H3 → H(1s) + H(1s) + H(1s). Fragmentation is induced by non-adiabatic couplings. By collecting the temporal and spatial information of triple-coincidence fragment atoms from isolated molecules, we deduce the center-of-mass momentum-vector correlation (MVC) which we represent in Dalitz-plots. Here we undertake a thorough comparison of experimental MVCs of different vibrational 2sA′1-states of H3 and D3 with predictions from a theoretical model [1,2]. The agreement of modeled and measured MVCs impressively shows that the vector correlations are direct images of the product of the vibrational wavefunction and the spatial dependence of the non-adiabatic coupling operator responsible for the dissociation. Our comparison also indicates that propagation of the hydrogen atoms on the dissociative ground potential-surface plays only a minor role in shaping correlation features. Research supported by DFG HE 2525/9.
[1] U. Galster, Phys. Rev. A 81, 032517 (2010)
[2] H. Höffler et al., Phys. Rev. A 83, 042519 (2011)