SAMOP 2023 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 6: Poster I

MO 6.20: Poster

Dienstag, 7. März 2023, 16:30–19:00, Empore Lichthof

Towards understanding the enhancement of the circular dichroism in the ion yield of 3-methylcyclopentanone via tailored femtosecond laser pulses — •Sagnik Das, Jayanta Ghosh, Sudheendran Vasudevan, Hangyeol Lee, Nicolas Ladda, Simon Ranecky, Tonio Rosen, Arne Senftleben, Thomas Baumert, and Hendrike Braun — Institut für Physik, Universität Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel, Germany

One of the methods to differentiate between the two enantiomers of a chiral molecule is Circular Dichroism (CD). It arises due to the difference in absorption of left and right circularly polarised light. The difference in absorption can also be mapped to the difference in ionisation of the enantiomers and is known as CD in ion yield [1]. We use our home-built Time of Flight (ToF) mass spectrometer with twin peak [2] measurement setup to study the effect of linear chirp (GDD) on the anisotropy. The candidate molecule for this experiment is 3-methylcyclopentanone (3-MCP). We perform all the experiments at 309 nm, where 3-MCP shows enhancement of anisotropy, upto 10%. At this wavelength, a 1+1+1 resonance-enhanced multi-photon ionisation (REMPI) takes place in 3-MCP through the π^* ← n transition. We observed enhancement of anisotropy for chirped pulses, which we have compared to bandwidth limited pulses of equal peak intensity. Furthermore, we perform a pump-probe experiment to investigate the intermediate state dynamics.

[1] U. Boesl and A. Bornschlegl, ChemPhysChem, 7, 2085, 2006

[2] T. Ring et al., Rev. Sci. Instrum., 92, 033001, 2021