Erlangen 2018 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 23: Strong laser fields - I (joint session A/MO)

A 23.1: Hauptvortrag

Dienstag, 6. März 2018, 14:00–14:30, K 2.019

Multiphoton Ionization of Chiral Molecules — •Thomas Baumert — Institut fuer Physik der Universitaet Kassel, Germany

Molecular chirality is widely recognized for its relevance to the building blocks of life and its vital role for medicine and health. Chiral recognition in the gas phase using electromagnetic radiation is an emerging research field and promising for fundamental research as well as for applications due to the non-interacting nature of molecules in the gas phase. Photoelectron angular distributions after one photon or multiphoton ionization turned out to be especially sensitive to that end and are usually measured by velocity map imaging (VMI) techniques. The corresponding circular dichroism is termed photoelectron circular dichroism (PECD). Based on electric dipole interaction, its magnitude of up to a few ten percent typically surpasses that of other chiroptical techniques and can be turned into a highly sensitive analytic tool with respect to investigation of enantiomeric excess. Resonance-enhanced multi-photon ionization (REMPI) gives access to electronic intermediates and, with the help of femtosecond laser excitation and ionization, PECD has been demonstrated on bicyclic ketones. As more angular momentum can be transferred in a multiphoton process in comparison to single photon ionization, higher order nodal structures were observed. An exploration of the nuclear and electron dynamics of the intermediate resonance may stimulate the development of laser driven purification schemes. In this talk I will present the field and our experiments. References are compiled for example in our latest publication: Kastner et al. JCP 2017, Vol. 147, 013926 (9 pp)