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MO: Fachverband Molekülphysik
MO 20: Theory: Molecular Dynamics
MO 20.4: Vortrag
Donnerstag, 26. März 2015, 15:30–15:45, PH/SR106
Transition state spectroscopy of the [H,C,N] molecular system — •Georg Ch. Mellau1,2, Robert W. Field2, Oleg L. Polyansky3,4, and Alexandra A. Kyuberis4 — 1Physikalisch-Chemisches Institut, Justus-Liebig-Universität Giessen, Germany — 2Department of Chemistry, MIT, Cambridge, MA, USA — 3Department of Physics and Astronomy, University College London, Gower St, London, UK — 4Institute of Applied Physics, Russian Academy of Science,46 Uljanov Street ,Nizhny Novgorod, Russia
In this work we study the molecular eigenstates at the transition state of the HCN<->HNC isomerization using our set of vibrationally assigned ab initio rovibrational eigenenergies. As the vibrational excitation energy approaches the isomerization barrier, the eigenstates show a vibrational angular momentum dependent Dixon-dip like trend [1], which correlates with the semiclassical pattern of the level spacings [2]. Based on this analysis, we can determine the proximity of an eigenstate to the effective isomerization barrier. The barrier proximal "saddle point states" are found to be highly localized in the bending coordinate at the saddle point. Our picture explains why the localization takes place not only for pure bending states but also at higher energies, exactly when the eigenenergies match the effective barrier height corresponding to the extra energy in the excited stretch. Saddle point localized states have been reported in [3]. [1] G. Ch. Mellau, J. Chem. Phys. 133, 7164303 (2010) [2] J. Baraban et all., in prep. (2014) [3] J. R. Henderson et all. J. Chem. Soc. Faraday Trans. 88, 328 (1992)