Berlin 2014 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 10: Posters 2: Biomolecules, Energy Transfer, Clusters, Quantum Chemistry, Molecular Dynamics and Chirality

MO 10.24: Poster

Dienstag, 18. März 2014, 16:30–18:30, Spree-Palais

Photoelectron Circular Dichroism of Chiral Molecules from Multiphoton Ionization with Femtosecond Laser Pulses: Intensity and Ellipticity studies — Christian Lux¹, •Stefanie Züllighoven¹, Cristian Sarpe¹, Matthias Wollenhaupt², and Thomas Baumert¹ — ¹Universität Kassel, Institut für Physik und CINSaT, D–34132 Kassel, Germany — ²Carl von Ossietzky Universität Oldenburg, Institut für Physik, D–26129 Oldenburg, Germany

Photoelectron Circular Dichroism (PECD) - i.e. the difference of the Photoelectron Angular Distribution (PAD) from ionization with left circularly polarized light and the PAD from ionization with right circularly polarized light - shows asymmetries in the electron emission from chiral enantiomers relative to the light propagation direction and was so far investigated using synchrotron radiation [1]. The magnitude of PECD is several orders larger than typically chirooptical asymmetries. We have demonstrated that PECD on randomly oriented chiral enantiomers is accessible via a 2+1 REMPI (Resonance Enhanced Multi-Photon Ionization) using femtosecond laser pulses. We detected highly structured asymmetries in the ± 10% regime [2]. In this contribution we present our recent findings on the bicyclic Ketones Camphor, Norcamphor and Fenchone. From the results on variation of the laser intensity, we conclude an underlying dissociative ionization. The PECD can be unambiguously attributed to direct ionization of the parent ion. Ellipticity studies show the robustness of the PECD effect.
[1] I. Powis in S. A. Rice (Ed.): Adv. Chem. Phys. 138, 267-329 (2008)
[2] C. Lux et al., Angew. Chem. Int. Ed. 51, 5001-5005 (2012)